Frequencies for first 10,000 rows of consuba2 variable in nhamcsed2001 dataset :

 controlled |
  substance |
   code for |
    adverse |
    drug #2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          7        0.07        0.07
          2 |         11        0.11        0.18
          4 |          4        0.04        0.22
          6 |         31        0.31        0.53
          7 |          8        0.08        0.61
          . |      9,939       99.39      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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