Frequencies for first 10,000 rows of rn variable in nhamcsed1994 dataset : registered | nurse seen | Freq. Percent Cum. ------------+----------------------------------- 0 | 1,540 15.40 15.40 1 | 8,460 84.60 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016