Frequencies for first 10,000 rows of f_uca_hydro variable in linkpe2009psden dataset : Hydrocephal | us U | Freq. Percent Cum. ------------+----------------------------------- . | 10,000 100.00 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Dec 2015