Frequencies for first 10,000 rows of mri variable in nhamcsed2007 dataset :

    any mri |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,922       99.22       99.22
        yes |         78        0.78      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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