Frequencies for first 10,000 rows of contsub4 variable in nhamcsed2004 dataset :

 controlled substance code |
         for medication #4 |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        132        1.32        1.32
              schedule iii |         89        0.89        2.21
               schedule iv |         54        0.54        2.75
                schedule v |          4        0.04        2.79
                no control |      1,465       14.65       17.44
              undetermined |         61        0.61       18.05
                         . |      8,195       81.95      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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