Frequencies for first 10,000 rows of contsub5 variable in nhamcsopd1997 dataset :

 controlled |
  substance |
   code for |
 medication |
         #5 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         12        0.12        0.12
          3 |          4        0.04        0.16
          4 |         23        0.23        0.39
          5 |          2        0.02        0.41
          6 |        552        5.52        5.93
          7 |         27        0.27        6.20
          . |      9,380       93.80      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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