Frequencies for first 10,000 rows of contsub1 variable in nhamcsed1993 dataset :

 controlled |
  substance |
   code for |
    drug #1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        249        2.49        2.49
          3 |        232        2.32        4.81
          4 |        166        1.66        6.47
          5 |         15        0.15        6.62
          6 |      6,068       60.68       67.30
          7 |        358        3.58       70.88
          . |      2,912       29.12      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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