Frequencies for first 10,000 rows of tow_veh variable in person dataset : Towed | Trailing | Unit | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,044 90.44 90.44 1 | 78 0.78 91.22 . | 878 8.78 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Apr 2016