How to insert comment next to each data point in Google chart

Hi I am using Google chart API (with php) in my project to show some chart like line, pie, bar etc. I want to insert a comment next to each data point on a chart that's开发者_如何学Go created, so that this data can store to the database.

Eg: I have a trend line for 5 years. The values being 10,13,22,15,14 For one or more of these points, I want to insert a comment in the graph that I create. Eg: The spike in Year3 has been due to blah blah.... How do I do this? Any tweaks? Please help!!!

Thanks in advance.

LOOK ON Dynamic Icon Markers,

in http://code.google.com/apis/chart/docs/chart_params.html