Frequencies for first 10,000 rows of contsub3 variable in namcs2000 dataset :

 controlled |
  substance |
   code for |
 medication |
         #3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         12        0.12        0.12
          3 |         28        0.28        0.40
          4 |         67        0.67        1.07
          5 |         11        0.11        1.18
          6 |      1,924       19.24       20.42
          7 |        101        1.01       21.43
          . |      7,857       78.57      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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