Frequencies for first 10,000 rows of contsub2 variable in nhamcsopd2006 dataset :

       for rx2, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               Schedule II |        143        1.43        1.43
              Schedule III |        102        1.02        2.45
               Schedule IV |        197        1.97        4.42
                Schedule V |         21        0.21        4.63
                No control |      3,737       37.37       42.00
              Undetermined |        126        1.26       43.26
                         . |      5,674       56.74      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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