Frequencies for first 10,000 rows of xray variable in nhamcsopd2006 dataset :

      x-ray |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,327       93.27       93.27
        Yes |        673        6.73      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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