Frequencies for first 10,000 rows of contsub4 variable in namcs1998 dataset :

 controlled |
  substance |
   code for |
 medication |
         #4 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |          4        0.04        0.04
          3 |         13        0.13        0.17
          4 |         47        0.47        0.64
          5 |          3        0.03        0.67
          6 |        939        9.39       10.06
          7 |         18        0.18       10.24
          . |      8,976       89.76      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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