Frequencies for first 10,000 rows of contsub2 variable in nhamcsed1996 dataset :

 controlled |
  substance |
   code for |
    drug #2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        155        1.55        1.55
          3 |        163        1.63        3.18
          4 |        103        1.03        4.21
          5 |         18        0.18        4.39
          6 |      3,303       33.03       37.42
          7 |        144        1.44       38.86
          . |      6,114       61.14      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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