Frequencies for first 10,000 rows of contsub2 variable in namcs1996 dataset :

 controlled |
  substance |
   code for |
 medication |
         #2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         66        0.66        0.66
          3 |        161        1.61        2.27
          4 |        436        4.36        6.63
          5 |         48        0.48        7.11
          6 |      6,511       65.11       72.22
          7 |        184        1.84       74.06
          . |      2,594       25.94      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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