Frequencies for first 10,000 rows of contsub6 variable in nhamcsopd2004 dataset :

 controlled substance code |
         for medication #6 |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |         36        0.36        0.36
              schedule iii |         10        0.10        0.46
               schedule iv |         35        0.35        0.81
                no control |        939        9.39       10.20
              undetermined |         24        0.24       10.44
                         . |      8,956       89.56      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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