Frequencies for first 10,000 rows of tow_veh variable in person dataset : Towed | Trailing | Unit | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,036 90.36 90.36 1 | 99 0.99 91.35 . | 865 8.65 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Apr 2016