Frequencies for first 10,000 rows of ddimer variable in nhamcsed2014 dataset :

    D-dimer |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,794       97.94       97.94
        Yes |        206        2.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 11 Apr 2017