Frequencies for first 10,000 rows of contsub1 variable in nhamcsopd2009 dataset :

       for rx1, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        282        2.82        2.82
              schedule iii |        116        1.16        3.98
               schedule iv |        180        1.80        5.78
                schedule v |         12        0.12        5.90
                no control |      6,020       60.20       66.10
              undetermined |        126        1.26       67.36
        multiple schedules |         26        0.26       67.62
                         . |      3,238       32.38      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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