Frequencies for first 10,000 rows of ekg variable in namcs2005 dataset : ekg/ecg | (electrocar | diogram) | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,689 96.89 96.89 1 | 311 3.11 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016