Frequencies for first 10,000 rows of staffphy variable in nhamcsed1992 dataset : Staff | physician | seen | Freq. Percent Cum. ------------+----------------------------------- 0 | 1,310 13.10 13.10 1 | 8,690 86.90 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016