Frequencies for first 10,000 rows of repeac variable in natl1994 dataset : Repeat | C-section | Freq. Percent Cum. ------------+----------------------------------- 1 | 828 8.28 8.28 2 | 9,150 91.50 99.78 9 | 22 0.22 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015