Frequencies for first 10,000 rows of contsub4 variable in nhamcsed2006 dataset :

       for rx4, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        123        1.23        1.23
              schedule iii |         85        0.85        2.08
               schedule iv |         48        0.48        2.56
                schedule v |          4        0.04        2.60
                no control |        938        9.38       11.98
              undetermined |         30        0.30       12.28
                         . |      8,772       87.72      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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