Frequencies for first 10,000 rows of contsub1 variable in nhamcsed1998 dataset :

 controlled |
  substance |
   code for |
    drug #1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        300        3.00        3.00
          3 |        213        2.13        5.13
          4 |        205        2.05        7.18
          5 |          8        0.08        7.26
          6 |      5,968       59.68       66.94
          7 |        165        1.65       68.59
          . |      3,141       31.41      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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