Frequencies for first 10,000 rows of f_mpcb_u variable in natlterr2010 dataset : Month | Prenatal | Care Began | (mpcb | Freq. Percent Cum. ------------+----------------------------------- 0 | 6,584 65.84 65.84 1 | 3,416 34.16 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015