Frequencies for first 10,000 rows of contsub21 variable in namcs2015 dataset :

 Controlled |
  substance |
   code for |
 medication |
        #21 |      Freq.     Percent        Cum.
------------+-----------------------------------
          3 |          2        0.02        0.02
          4 |          1        0.01        0.03
          6 |         44        0.44        0.47
          . |      9,953       99.53      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 25 Oct 2017