Frequencies for first 10,000 rows of ab_aven6 variable in natlterr2005 dataset : Assisted | Ventilation | >6 hrs R | Freq. Percent Cum. ------------+----------------------------------- | 6,255 62.55 62.55 N | 3,667 36.67 99.22 Y | 78 0.78 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015