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

   CT scan- |
       head |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,305       93.05       93.05
        Yes |        695        6.95      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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