Frequencies for first 10,000 rows of contsub6 variable in nhamcsopd2009 dataset :

       for rx6, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |         31        0.31        0.31
              schedule iii |         15        0.15        0.46
               schedule iv |         69        0.69        1.15
                schedule v |          8        0.08        1.23
                no control |      1,531       15.31       16.54
              undetermined |         20        0.20       16.74
        multiple schedules |          3        0.03       16.77
                         . |      8,323       83.23      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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