Frequencies for first 10,000 rows of haz_carg variable in vehicle dataset : Hazardous | Cargo | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,930 99.30 99.30 1 | 29 0.29 99.59 9 | 41 0.41 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 18 Apr 2016