Frequencies for first 10,000 rows of ab_aven1 variable in natlterr2005 dataset : Assisted | Ventilation | R | Freq. Percent Cum. ------------+----------------------------------- | 6,255 62.55 62.55 N | 3,654 36.54 99.09 Y | 91 0.91 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015