Valerie,
If you are doing this as a bar graph you may want to consider doing it in excel. Although I am sure there are ways of doing it in Stata they are pretty complicated (several people were dealing with the same issue in lab last week and we were unable to figure out a simple way to make it work). In excel however it is pretty straightforward, just enter the percentages into cells and make the appropriate graph.
Doing it in STATA is more difficult. You can see some examples in the pdf on bar graphs here http://www.stata.com/manuals13/g-2graphbar.pdf (page 27 has an example). Let us know more details if excel doesn't work for your project.
Sofia