Frequencies for first 10,000 rows of contsub1 variable in nhamcsopd2011 dataset :

      Controlled substance |
status code for Medication |
                        #1 |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               Schedule II |        218        2.18        2.18
              Schedule III |         75        0.75        2.93
               Schedule IV |        166        1.66        4.59
                Schedule V |         10        0.10        4.69
                No control |      6,342       63.42       68.11
              Undetermined |        134        1.34       69.45
        Multiple schedules |         17        0.17       69.62
                         . |      3,038       30.38      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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