Frequencies for first 10,000 rows of contsub5 variable in nhamcsopd2002 dataset :

 controlled |
  substance |
   code for |
 medication |
         #5 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         22        0.22        0.22
          3 |          7        0.07        0.29
          4 |         41        0.41        0.70
          5 |          2        0.02        0.72
          6 |        768        7.68        8.40
          7 |         29        0.29        8.69
          . |      9,131       91.31      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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