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		<text> 0</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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	<g transform="translate(67,305)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:end">
		<text> 50</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
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	<g transform="translate(67,268)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:end">
		<text> 100</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
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	<g transform="translate(67,232)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:end">
		<text> 150</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
	<path d='M84,191 L782,191 '></path>
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M84,191 L75,191 M782,191 L791,191 '></path>
	<g transform="translate(67,195)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:end">
		<text> 200</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M84,155 L75,155 M782,155 L791,155 '></path>
	<g transform="translate(67,159)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:end">
		<text> 250</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M84,118 L75,118 M782,118 L791,118 '></path>
	<g transform="translate(67,122)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:end">
		<text> 300</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
	<path d='M84,82 L782,82 '></path>
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M84,82 L75,82 M782,82 L791,82 '></path>
	<g transform="translate(67,86)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:end">
		<text> 350</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M84,45 L75,45 M782,45 L791,45 '></path>
	<g transform="translate(67,49)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:end">
		<text> 400</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
	<path d='M84,9 L782,9 '></path>
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M84,9 L75,9 M782,9 L791,9 '></path>
	<g transform="translate(67,13)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:end">
		<text> 450</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
	<path d='M107,337 L107,9 '></path>
</g>
<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
</g>
<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M107,337 L107,346 M107,9 L107,0 '></path>
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		<text> 1910</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
	<path d='M184,337 L184,9 '></path>
</g>
<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
</g>
<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M184,337 L184,346 M184,9 L184,0 '></path>
	<g transform="translate(184,368)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:middle">
		<text> 1920</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
</g>
<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
	<path d='M260,337 L260,9 '></path>
</g>
<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
</g>
<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M260,337 L260,346 M260,9 L260,0 '></path>
	<g transform="translate(260,368)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:middle">
		<text> 1930</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
</g>
<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
	<path d='M337,337 L337,9 '></path>
</g>
<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
</g>
<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M337,337 L337,346 M337,9 L337,0 '></path>
	<g transform="translate(337,368)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:middle">
		<text> 1940</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
	<path d='M414,337 L414,9 '></path>
</g>
<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
</g>
<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M414,337 L414,346 M414,9 L414,0 '></path>
	<g transform="translate(414,368)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:middle">
		<text> 1950</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
	<path d='M491,337 L491,9 '></path>
</g>
<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
</g>
<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M491,337 L491,346 M491,9 L491,0 '></path>
	<g transform="translate(491,368)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:middle">
		<text> 1960</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
	<path d='M567,337 L567,9 '></path>
</g>
<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
</g>
<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M567,337 L567,346 M567,9 L567,0 '></path>
	<g transform="translate(567,368)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:middle">
		<text> 1970</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
	<path d='M644,337 L644,9 '></path>
</g>
<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M644,337 L644,346 M644,9 L644,0 '></path>
	<g transform="translate(644,368)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:middle">
		<text> 1980</text>
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:0.20">
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:0.20">
	<path d='M721,337 L721,9 '></path>
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<g style="fill:none; color:gray; stroke:currentColor; stroke-width:1.00">
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<g style="fill:none; color:black; stroke:currentColor; stroke-width:1.00">
	<path d='M721,337 L721,346 M721,9 L721,0 '></path>
	<g transform="translate(721,368)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:middle">
		<text> 1990</text>
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	<path d='M84,337 L782,337 L782,9 L84,9 L84,337 '></path>
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		<text>Number of references</text>
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		<text>Year of publication</text>
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