Frequencies for first 10,000 rows of contsub2 variable in namcs2000 dataset :

 controlled |
  substance |
   code for |
 medication |
         #2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         15        0.15        0.15
          3 |         81        0.81        0.96
          4 |         98        0.98        1.94
          5 |         25        0.25        2.19
          6 |      3,407       34.07       36.26
          7 |        181        1.81       38.07
          . |      6,193       61.93      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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