Frequencies for first 10,000 rows of drg4ing4 variable in nhamcsed1996 dataset :

 ingredient |
code #4 for |
    drug #4 |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,991       99.91       99.91
      54468 |          1        0.01       99.92
      55180 |          4        0.04       99.96
      55755 |          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