Frequencies for first 10,000 rows of drg4ing5 variable in nhamcsopd1998 dataset :

 ingredient |
code #5 for |
 medication |
         #4 |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,994       99.94       99.94
      55520 |          1        0.01       99.95
      55755 |          1        0.01       99.96
      56185 |          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