Hi!
There is a way to change the denominator using PROC TABULATE code. It involves the use of the angle brackets '<>' and understanding which of the class variables you list inside the angle brackets. It is described in the SAS Help files under the topic:
"Specifying a Denominator for the PCTSUM Statistic".
So if you go to SAS Help and search for the words, "denominator" and "PCTSUM", you should find a program that illustrates how you would write this code. This article/sample also has a more advanced example of using a special denominator definition with PROC TABULATE:
http://support.sas.com/documentation/periodicals/obs/obswww16/index.html
However, if all you want is a percent of ROW or percent of COLUMN (instead of percent of Grand Total), keep in mind that you can select ROWPCTSUM or COLPCTSUM as the statistic for PROC TABULATE from within the EG Summary Table drag 'n drop interface.
One good way to test the ROWPCTSUM and COLPCTSUM statistics is to take a small dataset, like SASHELP.CLASS or SASHELP.SHOES and create several tables using these different statistics and compare the results to see which might be what you want. Be sure to use the ALL class variable in the ROW and COLUMN dimension so you can see where the 100%'s are showing up (lower right hand cell, along the rows or along the columns). Also, be aware of the fact that PROC TABULATE does an automatic multiply by 100 when calculating these statistics.
Good luck!
cynthia