Frequencies for first 10,000 rows of contsub4 variable in nhamcsed2002 dataset :

 controlled |
  substance |
   code for |
    drug #4 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |         63        0.63        0.63
          3 |         48        0.48        1.11
          4 |         50        0.50        1.61
          5 |          2        0.02        1.63
          6 |        984        9.84       11.47
          7 |         45        0.45       11.92
          . |      8,808       88.08      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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