Frequencies for first 10,000 rows of contsub4 variable in nhamcsed1994 dataset :

 controlled |
  substance |
   code for |
    drug #4 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         13        0.13        0.13
          3 |         25        0.25        0.38
          4 |         33        0.33        0.71
          5 |          2        0.02        0.73
          6 |        637        6.37        7.10
          7 |         53        0.53        7.63
          . |      9,237       92.37      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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