Frequencies for first 10,000 rows of contsub4 variable in nhamcsopd2003 dataset :

 controlled substance code |
         for medication #4 |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |         61        0.61        0.61
              schedule iii |         27        0.27        0.88
               schedule iv |         73        0.73        1.61
                schedule v |          2        0.02        1.63
                no control |      1,559       15.59       17.22
              undetermined |         49        0.49       17.71
                         . |      8,229       82.29      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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