Frequencies for first 10,000 rows of herpes variable in natlterr2001 dataset : Genital | herpes | Freq. Percent Cum. ------------+----------------------------------- 1 | 27 0.27 0.27 2 | 9,950 99.50 99.77 8 | 20 0.20 99.97 9 | 3 0.03 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015