Frequencies for first 10,000 rows of contsub7 variable in nhamcsopd2008 dataset :

       for rx7, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |         28        0.28        0.28
              schedule iii |         12        0.12        0.40
               schedule iv |         38        0.38        0.78
                schedule v |          9        0.09        0.87
                no control |      1,118       11.18       12.05
              undetermined |         16        0.16       12.21
                         . |      8,779       87.79      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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