Frequencies for first 10,000 rows of tow_veh variable in vehicle dataset : Towed | Trailing | Unit | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,925 99.25 99.25 1 | 75 0.75 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Apr 2016