Frequencies for first 10,000 rows of f_ab_nicu variable in natlterr2007 dataset : Admission | to NICU | (ab_nicu) R | Freq. Percent Cum. ------------+----------------------------------- 0 | 6,170 61.70 61.70 1 | 3,830 38.30 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015