Frequencies for first 10,000 rows of f_urf_phyper variable in natlterr2008 dataset : Pregnancy | Associated | Hypertensio | n | (urf_phyper | ) U;R | Freq. Percent Cum. ------------+----------------------------------- 0 | 1,343 13.43 13.43 1 | 8,657 86.57 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 3 May 2016