Frequencies for first 10,000 rows of contsub4 variable in nhamcsopd2004 dataset :

 controlled substance code |
         for medication #4 |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |         62        0.62        0.62
              schedule iii |         11        0.11        0.73
               schedule iv |         70        0.70        1.43
                schedule v |          3        0.03        1.46
                no control |      1,691       16.91       18.37
              undetermined |         42        0.42       18.79
                         . |      8,121       81.21      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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