Frequencies for first 10,000 rows of contsub1 variable in nhamcsed2007 dataset :

       for rx1, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        711        7.11        7.11
              schedule iii |        559        5.59       12.70
               schedule iv |        251        2.51       15.21
                schedule v |         15        0.15       15.36
                no control |      6,126       61.26       76.62
              undetermined |        104        1.04       77.66
                         . |      2,234       22.34      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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