Frequencies for first 10,000 rows of contsub3 variable in namcs2007 dataset :

    controlled status code |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
schedule i (research only) |          1        0.01        0.01
               schedule ii |         47        0.47        0.48
              schedule iii |         55        0.55        1.03
               schedule iv |        140        1.40        2.43
                schedule v |         23        0.23        2.66
                no control |      3,133       31.33       33.99
              undetermined |         68        0.68       34.67
                         . |      6,533       65.33      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

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