Frequencies for first 10,000 rows of blodpres variable in nhamcsopd2005 dataset : blood | pressure | taken | Freq. Percent Cum. ------------+----------------------------------- no | 3,557 35.57 35.57 yes | 6,443 64.43 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016