Frequencies for first 10,000 rows of chestxry variable in nhamcsed1993 dataset :

chest x-ray |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      8,322       83.22       83.22
          1 |      1,678       16.78      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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