Frequencies for first 10,000 rows of xray variable in namcs2013 dataset :

      X-ray |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,401       94.01       94.01
        Yes |        599        5.99      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 27 Mar 2017