Frequencies for first 10,000 rows of contsub2 variable in nhamcsed2007 dataset :

       for rx2, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        395        3.95        3.95
              schedule iii |        351        3.51        7.46
               schedule iv |        167        1.67        9.13
                schedule v |         18        0.18        9.31
                no control |      4,187       41.87       51.18
              undetermined |         57        0.57       51.75
                         . |      4,825       48.25      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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