Frequencies for first 10,000 rows of contsub4 variable in namcs1993 dataset :

 controlled |
  substance |
   code for |
 medication |
         #4 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |          4        0.04        0.04
          3 |         14        0.14        0.18
          4 |         42        0.42        0.60
          5 |          7        0.07        0.67
          6 |        870        8.70        9.37
          7 |         26        0.26        9.63
          . |      9,037       90.37      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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