Frequencies for first 10,000 rows of contsub6 variable in nhamcsed1997 dataset :

 controlled |
  substance |
   code for |
    drug #6 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |          9        0.09        0.09
          3 |          8        0.08        0.17
          4 |         14        0.14        0.31
          5 |          3        0.03        0.34
          6 |        177        1.77        2.11
          7 |          6        0.06        2.17
          . |      9,783       97.83      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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