Frequencies for first 10,000 rows of contsub4 variable in nhamcsed2007 dataset :

       for rx4, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        137        1.37        1.37
              schedule iii |        106        1.06        2.43
               schedule iv |         65        0.65        3.08
                schedule v |          4        0.04        3.12
                no control |      1,254       12.54       15.66
              undetermined |         24        0.24       15.90
                         . |      8,410       84.10      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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