Frequencies for first 10,000 rows of contsub2 variable in nhamcsed2006 dataset :

       for rx2, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        389        3.89        3.89
              schedule iii |        333        3.33        7.22
               schedule iv |        153        1.53        8.75
                schedule v |         12        0.12        8.87
                no control |      3,864       38.64       47.51
              undetermined |         88        0.88       48.39
                         . |      5,161       51.61      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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