Frequencies for first 10,000 rows of rh variable in natl1998 dataset : Rh | sensitizati | on | Freq. Percent Cum. ------------+----------------------------------- 1 | 74 0.74 0.74 2 | 9,926 99.26 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015