Frequencies for first 10,000 rows of contsub3 variable in nhamcsed2006 dataset :

       for rx3, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        230        2.30        2.30
              schedule iii |        168        1.68        3.98
               schedule iv |         68        0.68        4.66
                schedule v |         12        0.12        4.78
                no control |      1,930       19.30       24.08
              undetermined |         48        0.48       24.56
                         . |      7,544       75.44      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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