Frequencies for first 10,000 rows of repeac variable in natl1993 dataset : Repeat | C-section | Freq. Percent Cum. ------------+----------------------------------- 1 | 847 8.47 8.47 2 | 9,143 91.43 99.90 9 | 10 0.10 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015