Frequencies for first 10,000 rows of contsub7 variable in nhamcsopd2004 dataset :

 controlled substance code |
         for medication #7 |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |         23        0.23        0.23
              schedule iii |          8        0.08        0.31
               schedule iv |         30        0.30        0.61
                schedule v |          2        0.02        0.63
                no control |        678        6.78        7.41
              undetermined |         23        0.23        7.64
                         . |      9,236       92.36      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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