Frequencies for first 10,000 rows of visual variable in nhamcsopd2000 dataset : visual | acuity exam | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,535 95.35 95.35 1 | 465 4.65 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016