Frequencies for first 10,000 rows of contsub5 variable in nhamcsed2001 dataset :

 controlled |
  substance |
   code for |
    drug #5 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         13        0.13        0.13
          3 |         18        0.18        0.31
          4 |         32        0.32        0.63
          6 |        486        4.86        5.49
          7 |         41        0.41        5.90
          . |      9,410       94.10      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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