Frequencies for first 10,000 rows of echocard variable in namcs2013 dataset :

Echocardiog |
        ram |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,911       99.11       99.11
        Yes |         89        0.89      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 27 Mar 2017