Frequencies for first 10,000 rows of injury variable in natlterr2001 dataset : Birth | injury | Freq. Percent Cum. ------------+----------------------------------- 1 | 3 0.03 0.03 2 | 9,973 99.73 99.76 8 | 20 0.20 99.96 9 | 4 0.04 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015