Frequencies for first 10,000 rows of cbc variable in nhamcsed2013 dataset :

        CBC |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      6,516       65.16       65.16
        Yes |      3,484       34.84      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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