Frequencies for first 10,000 rows of retinal variable in nhamcsopd2009 dataset :

    retinal |
       exam |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,878       98.78       98.78
        yes |        122        1.22      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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