Frequencies for first 10,000 rows of contsub2 variable in nhamcsopd2007 dataset :

       for rx2, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        135        1.35        1.35
              schedule iii |         85        0.85        2.20
               schedule iv |        160        1.60        3.80
                schedule v |          8        0.08        3.88
                no control |      4,213       42.13       46.01
              undetermined |         72        0.72       46.73
                         . |      5,327       53.27      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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