Frequencies for first 10,000 rows of contsub6 variable in nhamcsopd2001 dataset :

 controlled |
  substance |
   code for |
 medication |
         #6 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         31        0.31        0.31
          3 |          5        0.05        0.36
          4 |         16        0.16        0.52
          5 |          4        0.04        0.56
          6 |        605        6.05        6.61
          7 |         39        0.39        7.00
          . |      9,300       93.00      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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