Frequencies for first 10,000 rows of contsub7 variable in nhamcsed2008 dataset :

       for rx7, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |         14        0.14        0.14
              schedule iii |          8        0.08        0.22
               schedule iv |         15        0.15        0.37
                schedule v |          2        0.02        0.39
                no control |        218        2.18        2.57
              undetermined |          2        0.02        2.59
                         . |      9,741       97.41      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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