Frequencies for first 10,000 rows of mri variable in nhamcsed2011 dataset :

        MRI |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,945       99.45       99.45
        Yes |         55        0.55      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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