Frequencies for first 10,000 rows of drg3ing4 variable in nhamcsopd2001 dataset :

 ingredient |
code #4 for |
 medication |
         #3 |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,994       99.94       99.94
      54713 |          1        0.01       99.95
      55755 |          3        0.03       99.98
      56193 |          1        0.01       99.99
      56310 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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