Frequencies for first 10,000 rows of contsub4 variable in nhamcsopd2001 dataset :

 controlled |
  substance |
   code for |
 medication |
         #4 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         21        0.21        0.21
          3 |          8        0.08        0.29
          4 |         43        0.43        0.72
          5 |          5        0.05        0.77
          6 |      1,355       13.55       14.32
          7 |         67        0.67       14.99
          . |      8,501       85.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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