Frequencies for first 10,000 rows of cardiac variable in natlterr1998 dataset : Cardiac | disease | Freq. Percent Cum. ------------+----------------------------------- 1 | 18 0.18 0.18 2 | 9,980 99.80 99.98 9 | 2 0.02 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015