Frequencies for first 10,000 rows of contsub6 variable in nhamcsed2006 dataset :

       for rx6, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |         16        0.16        0.16
              schedule iii |         15        0.15        0.31
               schedule iv |          7        0.07        0.38
                schedule v |          1        0.01        0.39
                no control |        198        1.98        2.37
              undetermined |          3        0.03        2.40
                         . |      9,760       97.60      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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