Frequencies for first 10,000 rows of cbc variable in nhamcsed2007 dataset :

        cbc |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      6,144       61.44       61.44
        yes |      3,856       38.56      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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