Frequencies for first 10,000 rows of exercise variable in nhamcsopd2010 dataset : exercise | Freq. Percent Cum. ------------+----------------------------------- no | 9,096 90.96 90.96 yes | 904 9.04 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016