Illustrator has only a rudimentary graphing ability. A User suggests using DeltaGraph at <http://www.spss.com/deltagraph/> for creating graphs in the Windows environment. I’ve not used it but they say it can create EPS output, which would be great. There is a downloadable demo version at that site. Another User suggests Origin as an excellent choice, and not too expensive (see <http://www.originlab.com/www/downloads/demo/index.cfm)> Origin can export graphs as vector EPS files that are fully editable in Illustrator. Other Users have said that creating graphs in Excel and exporting as PDFs to bring to Illustrator is another strategy that works.
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