Frequencies for first 10,000 rows of contsub2 variable in nhamcsopd2009 dataset :

       for rx2, controlled |
     substance status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |        167        1.67        1.67
              schedule iii |         68        0.68        2.35
               schedule iv |        181        1.81        4.16
                schedule v |         10        0.10        4.26
                no control |      4,363       43.63       47.89
              undetermined |         87        0.87       48.76
        multiple schedules |         11        0.11       48.87
                         . |      5,113       51.13      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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