Frequencies for first 10,000 rows of drg4ing4 variable in nhamcsed1999 dataset :

 ingredient |
code #4 for |
    drug #4 |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,993       99.93       99.93
      54465 |          1        0.01       99.94
      54468 |          1        0.01       99.95
      55180 |          4        0.04       99.99
      56193 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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