Frequencies for first 10,000 rows of contsub4 variable in nhamcsed1995 dataset :

 controlled |
  substance |
   code for |
    drug #4 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         29        0.29        0.29
          3 |         29        0.29        0.58
          4 |         33        0.33        0.91
          5 |          4        0.04        0.95
          6 |        678        6.78        7.73
          7 |         34        0.34        8.07
          . |      9,193       91.93      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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