Frequencies for first 10,000 rows of drg3ing4 variable in nhamcsopd1998 dataset :

 ingredient |
code #4 for |
 medication |
         #3 |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,990       99.90       99.90
      55105 |          1        0.01       99.91
      55710 |          1        0.01       99.92
      55755 |          4        0.04       99.96
      56193 |          3        0.03       99.99
      56265 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016