Frequencies for first 10,000 rows of contsub1 variable in nhamcsed1996 dataset :

 controlled |
  substance |
   code for |
    drug #1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        348        3.48        3.48
          3 |        317        3.17        6.65
          4 |        190        1.90        8.55
          5 |         16        0.16        8.71
          6 |      5,892       58.92       67.63
          7 |        234        2.34       69.97
          . |      3,003       30.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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