Frequencies for first 10,000 rows of contsub7 variable in nhamcsed2010 dataset :

    Controlled status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |         23        0.23        0.23
              schedule iii |         14        0.14        0.37
               schedule iv |         15        0.15        0.52
                no control |        263        2.63        3.15
              undetermined |          4        0.04        3.19
                         . |      9,681       96.81      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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