Frequencies for first 10,000 rows of contsub4 variable in nhamcsopd2008 dataset :

       for rx4, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |         58        0.58        0.58
              schedule iii |         30        0.30        0.88
               schedule iv |         85        0.85        1.73
                schedule v |         14        0.14        1.87
                no control |      2,486       24.86       26.73
              undetermined |         36        0.36       27.09
                         . |      7,291       72.91      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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