Frequencies for first 10,000 rows of contsub1 variable in nhamcsopd2004 dataset :

 controlled substance code |
         for medication #1 |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        231        2.31        2.31
              schedule iii |        149        1.49        3.80
               schedule iv |        181        1.81        5.61
                schedule v |         12        0.12        5.73
                no control |      5,756       57.56       63.29
              undetermined |        151        1.51       64.80
                         . |      3,520       35.20      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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