Frequencies for first 10,000 rows of contsub2 variable in nhamcsopd2003 dataset :

 controlled substance code |
         for medication #2 |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        152        1.52        1.52
              schedule iii |         59        0.59        2.11
               schedule iv |        123        1.23        3.34
                schedule v |         12        0.12        3.46
                no control |      3,455       34.55       38.01
              undetermined |         92        0.92       38.93
                         . |      6,107       61.07      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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