Frequencies for first 10,000 rows of ekg variable in namcs2007 dataset : ekg/ecg | (electrocar | diogram) | Freq. Percent Cum. ------------+----------------------------------- no | 9,738 97.38 97.38 yes | 262 2.62 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016