Frequencies for first 10,000 rows of haz_carg variable in vehicle dataset : Hazardous | Cargo | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,921 99.21 99.21 1 | 35 0.35 99.56 9 | 44 0.44 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 18 Apr 2016