Frequencies for first 10,000 rows of contsub3 variable in namcs1995 dataset :

 controlled |
  substance |
   code for |
 medication |
         #3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         11        0.11        0.11
          3 |         44        0.44        0.55
          4 |        113        1.13        1.68
          5 |         16        0.16        1.84
          6 |      1,979       19.79       21.63
          7 |         65        0.65       22.28
          . |      7,772       77.72      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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