Frequencies for first 10,000 rows of ekg variable in nhamcsed2013 dataset :

    EKG/ECG |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      8,099       80.99       80.99
        Yes |      1,901       19.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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