Frequencies for first 10,000 rows of haz_carg variable in vehicle dataset : Hazardous | Cargo | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,901 99.01 99.01 1 | 32 0.32 99.33 9 | 67 0.67 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 18 Apr 2016