Just copy & paste following code into url field of newly created bookmark:

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javascript:(function(){var%20tables=document.getElementsByTagName("table");var%20poll_table=tables[3];var%20labels=poll_table.getElementsByTagName("font");var%20values=poll_table.getElementsByTagName("span");var%20lab=[];for(var%20i=0;i<labels.length;i++)lab.push(labels[i].innerHTML);var%20num=[];for(var%20i=0;i<values.length;i++){if(values[i].parentNode.className=="comhead")num.push(/\d+/.exec(values[i].innerHTML))}var%20chl=lab.join("|");var%20chd=num.join(",");var%20chdmax=Math.max.apply(Math,num);var%20img=document.createElement('IMG');img.src="http://chart.apis.google.com/chart?chs=500x200&chd=t:"+chd+"&chds=0,"+chdmax+"&cht=p&chl="+chl+"&chf=bg,s,FFFFFF00";img.style.padding="1em";poll_table.parentNode.insertBefore(img,poll_table);})()

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Or, if you want to change something more easily, you can also use a version that loads a script from an external source:

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javascript:function%20loadScript(scriptURL){var%20s=document.createElement('SCRIPT');s.setAttribute('language','JavaScript');%20s.setAttribute('src',scriptURL);document.body.appendChild(s);}loadScript('http://alteredqualia.com/visualization/hn/hn_poll_graph.js');

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Note: Scraping is pretty fragile, it can break with any change of HN's html formatting.