Frequencies for first 10,000 rows of contsub1 variable in nhamcsed1992 dataset :

 Controlled |
  substance |
   code for |
    drug #1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        233        2.33        2.33
          3 |        205        2.05        4.38
          4 |        130        1.30        5.68
          5 |         32        0.32        6.00
          6 |      5,490       54.90       60.90
          7 |        281        2.81       63.71
          . |      3,629       36.29      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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