Frequencies for first 10,000 rows of contsub5 variable in nhamcsopd2009 dataset :

       for rx5, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |         38        0.38        0.38
              schedule iii |         23        0.23        0.61
               schedule iv |         79        0.79        1.40
                schedule v |          9        0.09        1.49
                no control |      1,993       19.93       21.42
              undetermined |         23        0.23       21.65
        multiple schedules |          4        0.04       21.69
                         . |      7,831       78.31      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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