Frequencies for first 10,000 rows of sch_bus variable in accident dataset : SCHOOLBUS | RELATED | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,965 99.65 99.65 1 | 35 0.35 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 18 Apr 2016