Frequencies for first 10,000 rows of drg4ing4 variable in nhamcsopd2001 dataset : ingredient | code #4 for | medication | #4 | Freq. Percent Cum. ------------+----------------------------------- | 9,996 99.96 99.96 55755 | 4 0.04 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016