Frequencies for first 10,000 rows of contsub1 variable in nhamcsed1997 dataset :

 controlled |
  substance |
   code for |
    drug #1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        340        3.40        3.40
          3 |        313        3.13        6.53
          4 |        225        2.25        8.78
          5 |         18        0.18        8.96
          6 |      6,035       60.35       69.31
          7 |        170        1.70       71.01
          . |      2,899       28.99      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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