How can I make the text marker be closer to the actual point on the graph?

http://chart.apis.google.com/chart?chtt=ACTION+COMICS &cht=lxy &chs=300x200 &chco=FF0000,00CC33,0066CC,FF9900 &chg=0,20 &chd=t:1,2,3,4,5,6|20,22,20,25,20,30|1,2,3,4,5,6|18,19,18,20,18,25 &chds=1,6,0,35,1,6,0,35 &chxt=x,y &chxr=0,1,6|1,0,30 &chxl=0:1|6|1:|0|15|30 &chm=o,FF0000,0,0,5,1|t21,FF0000,0,0,13,1|t22,FF0000,0,1,13,1| t20,FF0000,0,2,13,1|t25,FF0000,0,3,13,1|t20,FF0000,0,4,13,1| t30,FF0000,0,5,13,1 |t18,00CC33,1,0,13,1|t19,00CC33,1,1,13,1|t18,00CC33,1,2,13,1| t20,00CC33,1,3,13,1|t18,00CC33,1,4,13,1|t25,00CC33,1,5,13,1

I'm trying to duplicate (or improve upon) a graph like this:

http://www.hijinxcomics.com/images/cyclesheet.png

any pointers would be greatly appreciated

thanks,