Frequencies for first 10,000 rows of contsub4 variable in nhamcsed1998 dataset :

 controlled |
  substance |
   code for |
    drug #4 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         36        0.36        0.36
          3 |         31        0.31        0.67
          4 |         33        0.33        1.00
          5 |          2        0.02        1.02
          6 |        658        6.58        7.60
          7 |         20        0.20        7.80
          . |      9,220       92.20      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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