Frequencies for first 10,000 rows of contsub5 variable in nhamcsopd1999 dataset :

 controlled |
  substance |
   code for |
 medication |
         #5 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         13        0.13        0.13
          3 |          6        0.06        0.19
          4 |         31        0.31        0.50
          5 |          1        0.01        0.51
          6 |        684        6.84        7.35
          7 |         20        0.20        7.55
          . |      9,245       92.45      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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