Frequencies for first 10,000 rows of contsub2 variable in nhamcsopd2011 dataset :

      Controlled substance |
status code for Medication |
                        #2 |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               Schedule II |        125        1.25        1.25
              Schedule III |         37        0.37        1.62
               Schedule IV |        215        2.15        3.77
                Schedule V |          8        0.08        3.85
                No control |      4,510       45.10       48.95
              Undetermined |         78        0.78       49.73
        Multiple schedules |          7        0.07       49.80
                         . |      5,020       50.20      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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