Frequencies for first 10,000 rows of contsub3 variable in nhamcsed1999 dataset :

 controlled |
  substance |
   code for |
    drug #3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         95        0.95        0.95
          3 |        112        1.12        2.07
          4 |         61        0.61        2.68
          5 |         14        0.14        2.82
          6 |      1,647       16.47       19.29
          7 |        108        1.08       20.37
          . |      7,963       79.63      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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