Frequencies for first 10,000 rows of contsub2 variable in nhamcsed2001 dataset :

 controlled |
  substance |
   code for |
    drug #2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        225        2.25        2.25
          3 |        177        1.77        4.02
          4 |        141        1.41        5.43
          5 |         17        0.17        5.60
          6 |      3,669       36.69       42.29
          7 |        166        1.66       43.95
          . |      5,605       56.05      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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