Frequencies for first 10,000 rows of rn variable in nhamcsopd1994 dataset : registered | nurse seen | Freq. Percent Cum. ------------+----------------------------------- 0 | 4,338 43.38 43.38 1 | 5,662 56.62 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016