Frequencies for first 10,000 rows of contsub3 variable in nhamcsopd2008 dataset :

       for rx3, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        100        1.00        1.00
              schedule iii |         53        0.53        1.53
               schedule iv |        111        1.11        2.64
                schedule v |          9        0.09        2.73
                no control |      3,232       32.32       35.05
              undetermined |         48        0.48       35.53
                         8 |          8        0.08       35.61
                         . |      6,439       64.39      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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