Frequencies for first 10,000 rows of contsub1 variable in nhamcsed1995 dataset :

 controlled |
  substance |
   code for |
    drug #1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        325        3.25        3.25
          3 |        325        3.25        6.50
          4 |        169        1.69        8.19
          5 |         21        0.21        8.40
          6 |      5,885       58.85       67.25
          7 |        168        1.68       68.93
          . |      3,107       31.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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