Frequencies for first 10,000 rows of staffphy variable in nhamcsed1999 dataset : staff | physician | seen | Freq. Percent Cum. ------------+----------------------------------- 0 | 1,116 11.16 11.16 1 | 8,884 88.84 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016