Frequencies for first 10,000 rows of contsub1 variable in nhamcsopd1998 dataset :

 controlled |
  substance |
   code for |
 medication |
          # |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        266        2.66        2.66
          3 |         67        0.67        3.33
          4 |        129        1.29        4.62
          5 |          4        0.04        4.66
          6 |      5,671       56.71       61.37
          7 |        258        2.58       63.95
          . |      3,605       36.05      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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