Frequencies for first 10,000 rows of doa variable in nhamcsed2012 dataset :

        DOA |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,998       99.98       99.98
        Yes |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 7 Nov 2016