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

 mri/ct/pet |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,586       95.86       95.86
        Yes |        414        4.14      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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