Frequencies for first 10,000 rows of cardiac variable in natlterr1997 dataset : Cardiac | disease | Freq. Percent Cum. ------------+----------------------------------- 1 | 26 0.26 0.26 2 | 9,970 99.70 99.96 9 | 4 0.04 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015