Frequencies for first 10,000 rows of gestimp variable in natl1987 dataset : Gestation | Imputation | Flag | Freq. Percent Cum. ------------+----------------------------------- 1 | 1,799 17.99 17.99 . | 8,201 82.01 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 3 Jan 2016