Frequencies for first 10,000 rows of contsub3 variable in namcs1997 dataset :

 controlled |
  substance |
   code for |
 medication |
         #3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         23        0.23        0.23
          3 |         48        0.48        0.71
          4 |        186        1.86        2.57
          5 |         10        0.10        2.67
          6 |      2,714       27.14       29.81
          7 |         50        0.50       30.31
          . |      6,969       69.69      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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