Frequencies for first 10,000 rows of contsub8 variable in nhamcsed2006 dataset :

       for rx8, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |          2        0.02        0.02
                no control |         40        0.40        0.42
              undetermined |          3        0.03        0.45
                         . |      9,955       99.55      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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