Frequencies for first 10,000 rows of repeac variable in natl1996 dataset : Repeat | C-section | Freq. Percent Cum. ------------+----------------------------------- 1 | 814 8.14 8.14 2 | 9,173 91.73 99.87 9 | 13 0.13 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015