Frequencies for first 10,000 rows of sigcolon variable in namcs2007 dataset : sigmoidosco | py/colonosc | opy | Freq. Percent Cum. ------------+----------------------------------- no | 9,911 99.11 99.11 yes | 89 0.89 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016