Frequencies for first 10,000 rows of sch_bus variable in person dataset : SCHOOLBUS | RELATED | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,966 99.66 99.66 1 | 34 0.34 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 18 Apr 2016