Frequencies for first 10,000 rows of contsub5 variable in nhamcsopd1998 dataset :

 controlled |
  substance |
   code for |
 medication |
         #5 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |          4        0.04        0.04
          3 |          5        0.05        0.09
          4 |         21        0.21        0.30
          5 |          3        0.03        0.33
          6 |        639        6.39        6.72
          7 |         18        0.18        6.90
          . |      9,310       93.10      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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