Frequencies for first 10,000 rows of staffphy variable in nhamcsed1993 dataset : staff | physician | seen | Freq. Percent Cum. ------------+----------------------------------- 0 | 1,389 13.89 13.89 1 | 8,611 86.11 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016