Frequencies for first 10,000 rows of f_ab_vent6 variable in natl2011 dataset : Assisted | Ventilation | >6hrs | (ab_aven6) | R | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,984 99.84 99.84 1 | 16 0.16 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015