Frequencies for first 10,000 rows of contsub2 variable in nhamcsed1994 dataset :

 controlled |
  substance |
   code for |
    drug #2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         79        0.79        0.79
          3 |        128        1.28        2.07
          4 |        102        1.02        3.09
          5 |         22        0.22        3.31
          6 |      3,228       32.28       35.59
          7 |        219        2.19       37.78
          . |      6,222       62.22      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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