Frequencies for first 10,000 rows of cbc variable in nhamcsed2012 dataset :

        CBC |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      6,612       66.12       66.12
        Yes |      3,388       33.88      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 7 Nov 2016