Frequencies for first 10,000 rows of contsub4 variable in namcs2000 dataset :

 controlled |
  substance |
   code for |
 medication |
         #4 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |          5        0.05        0.05
          3 |          9        0.09        0.14
          4 |         53        0.53        0.67
          5 |          7        0.07        0.74
          6 |      1,123       11.23       11.97
          7 |         33        0.33       12.30
          . |      8,770       87.70      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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