Frequencies for first 10,000 rows of contsub6 variable in nhamcsed2000 dataset :

 controlled |
  substance |
   code for |
    drug #6 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         14        0.14        0.14
          3 |          5        0.05        0.19
          4 |          7        0.07        0.26
          5 |          1        0.01        0.27
          6 |        228        2.28        2.55
          7 |         19        0.19        2.74
          . |      9,726       97.26      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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