Frequencies for first 10,000 rows of contsub6 variable in namcs1998 dataset :

 controlled |
  substance |
   code for |
 medication |
         #6 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |          4        0.04        0.04
          3 |          3        0.03        0.07
          4 |         11        0.11        0.18
          5 |          1        0.01        0.19
          6 |        326        3.26        3.45
          7 |         11        0.11        3.56
          . |      9,644       96.44      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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