Frequencies for first 10,000 rows of echocard variable in nhamcsopd2011 dataset :

Echocardiog |
        ram |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,872       98.72       98.72
        Yes |        128        1.28      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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