Frequencies for first 10,000 rows of blodpres variable in nhamcsopd2007 dataset : blood | pressure | taken | Freq. Percent Cum. ------------+----------------------------------- no | 4,354 43.54 43.54 yes | 5,646 56.46 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016