Frequencies for first 10,000 rows of contsub5 variable in nhamcsed1996 dataset :

 controlled |
  substance |
   code for |
    drug #5 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         10        0.10        0.10
          3 |         15        0.15        0.25
          4 |         17        0.17        0.42
          5 |          2        0.02        0.44
          6 |        420        4.20        4.64
          7 |         24        0.24        4.88
          . |      9,512       95.12      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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