Frequencies for first 10,000 rows of distress variable in natl2001 dataset : Fetal | distress | Freq. Percent Cum. ------------+----------------------------------- 1 | 313 3.13 3.13 2 | 9,683 96.83 99.96 8 | 3 0.03 99.99 9 | 1 0.01 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015