Frequencies for first 10,000 rows of contsub1 variable in nhamcsed2006 dataset :

       for rx1, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        702        7.02        7.02
              schedule iii |        561        5.61       12.63
               schedule iv |        228        2.28       14.91
                schedule v |         23        0.23       15.14
                no control |      6,079       60.79       75.93
              undetermined |        116        1.16       77.09
                         . |      2,291       22.91      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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