Frequencies for first 10,000 rows of contsub1 variable in nhamcsopd2000 dataset :

 controlled |
  substance |
   code for |
 medication |
          # |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        258        2.58        2.58
          3 |         91        0.91        3.49
          4 |        152        1.52        5.01
          5 |         12        0.12        5.13
          6 |      5,254       52.54       57.67
          7 |        229        2.29       59.96
          . |      4,004       40.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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