Frequencies for first 10,000 rows of contsub2 variable in nhamcsed2008 dataset :

       for rx2, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        494        4.94        4.94
              schedule iii |        350        3.50        8.44
               schedule iv |        164        1.64       10.08
                schedule v |         15        0.15       10.23
                no control |      4,195       41.95       52.18
              undetermined |        104        1.04       53.22
        multiple schedules |         40        0.40       53.62
                         . |      4,638       46.38      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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