Frequencies for first 10,000 rows of drg4ing5 variable in nhamcsopd1997 dataset : ingredient | code #5 for | medication | #4 | Freq. Percent Cum. ------------+----------------------------------- | 9,990 99.90 99.90 56185 | 7 0.07 99.97 56192 | 2 0.02 99.99 56193 | 1 0.01 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016