Frequencies for first 10,000 rows of contsub4 variable in namcs1996 dataset :

 controlled |
  substance |
   code for |
 medication |
         #4 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         14        0.14        0.14
          3 |         27        0.27        0.41
          4 |         80        0.80        1.21
          5 |         11        0.11        1.32
          6 |      1,823       18.23       19.55
          7 |         29        0.29       19.84
          . |      8,016       80.16      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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