Frequencies for first 10,000 rows of contsub4 variable in nhamcsed1996 dataset :

 controlled |
  substance |
   code for |
    drug #4 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         32        0.32        0.32
          3 |         33        0.33        0.65
          4 |         38        0.38        1.03
          5 |          3        0.03        1.06
          6 |        770        7.70        8.76
          7 |         48        0.48        9.24
          . |      9,076       90.76      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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