Frequencies for first 10,000 rows of contsub3 variable in nhamcsed1998 dataset :

 controlled |
  substance |
   code for |
    drug #3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         87        0.87        0.87
          3 |         40        0.40        1.27
          4 |         68        0.68        1.95
          5 |          2        0.02        1.97
          6 |      1,493       14.93       16.90
          7 |         58        0.58       17.48
          . |      8,252       82.52      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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