Frequencies for first 10,000 rows of contsub6 variable in nhamcsed2008 dataset :

       for rx6, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |         35        0.35        0.35
              schedule iii |         16        0.16        0.51
               schedule iv |         18        0.18        0.69
                schedule v |          1        0.01        0.70
                no control |        375        3.75        4.45
              undetermined |          5        0.05        4.50
        multiple schedules |          2        0.02        4.52
                         . |      9,548       95.48      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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