Frequencies for first 10,000 rows of lmpyr variable in natl1982 dataset : Year Last | Normal | Menses | Began | Freq. Percent Cum. ------------+----------------------------------- - | 167 1.67 1.67 1 | 9,812 98.12 99.79 2 | 21 0.21 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 3 Jan 2016