Frequencies for first 10,000 rows of contsub3 variable in namcs1998 dataset :

 controlled |
  substance |
   code for |
 medication |
         #3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         13        0.13        0.13
          3 |         39        0.39        0.52
          4 |         72        0.72        1.24
          5 |          6        0.06        1.30
          6 |      1,758       17.58       18.88
          7 |         43        0.43       19.31
          . |      8,069       80.69      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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