Frequencies for first 10,000 rows of contsub2 variable in namcs1995 dataset :

 controlled |
  substance |
   code for |
 medication |
         #2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         18        0.18        0.18
          3 |        123        1.23        1.41
          4 |        194        1.94        3.35
          5 |         52        0.52        3.87
          6 |      3,716       37.16       41.03
          7 |        172        1.72       42.75
          . |      5,725       57.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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