Frequencies for first 10,000 rows of contsub1 variable in nhamcsed2000 dataset :

 controlled |
  substance |
   code for |
    drug #1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        427        4.27        4.27
          3 |        315        3.15        7.42
          4 |        195        1.95        9.37
          5 |         15        0.15        9.52
          6 |      5,914       59.14       68.66
          7 |        189        1.89       70.55
          . |      2,945       29.45      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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