jwill

Your original URL string:

http://chart.apis.google.com/chart?cht=bhs&chs=500x600&chco=FF9900|FF3300&chxt=r,x,t&chxl=0:|ManningBooks|groovymag|graemerocher|iamthechad|ldaley|GeertjanW|HamletDRC|snaglepus|daveklein|gr8conf|RobertFischer|dima767|glaforge|grailsmx|mittie|grailsframework|wangjammer5|grailspodcast|hansamann|aalmiray&chd=t:27,20,20,18,16,15,15,15,13,12,10,10,9,9,8,8,8,7,7,7

Tweaked URL string:

http://chart.apis.google.com/chart?cht=bhs&chs=500x600&chco=FF9900|FF3300&chxt=r,x,t&chxl=0:|ManningBooks|groovymag|graemerocher|iamthechad|ldaley|GeertjanW|HamletDRC|snaglepus|daveklein|gr8conf|RobertFischer|dima767|glaforge|grailsmx|mittie|grailsframework|wangjammer5|hansamann|grailspodcast|aalmiray|1:|0|10|20|27|2:|0|10|20|27&chd=t:27,20,19,18,16,15,15,15,13,12,10,10,9,9,8,8,8,7,7,7&chds=0,27

What I added: 
scale="${[min1, max1, minN, maxN]}"     (translates to chds in the final string)