Frequencies for first 10,000 rows of contsub3 variable in namcs2009 dataset :

    controlled status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
               schedule ii |         57        0.57        0.57
              schedule iii |         75        0.75        1.32
               schedule iv |        143        1.43        2.75
                schedule v |         20        0.20        2.95
                no control |      3,640       36.40       39.35
              undetermined |         65        0.65       40.00
        multiple schedules |          8        0.08       40.08
                         . |      5,992       59.92      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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