Frequencies for first 10,000 rows of contsub2 variable in namcs1999 dataset :

 controlled |
  substance |
   code for |
 medication |
         #2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         43        0.43        0.43
          3 |         65        0.65        1.08
          4 |        210        2.10        3.18
          5 |         24        0.24        3.42
          6 |      3,154       31.54       34.96
          7 |        126        1.26       36.22
          . |      6,378       63.78      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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