Frequencies for first 10,000 rows of rail variable in accident dataset : rail grade | crossing | identifier | Freq. Percent Cum. ------------+----------------------------------- 0 | 1 0.01 0.01 000000 | 3 0.03 0.04 0000000 | 9,957 99.57 99.61 003370N | 1 0.01 99.62 057352R | 1 0.01 99.63 272483J | 1 0.01 99.64 339808G | 1 0.01 99.65 352190C | 1 0.01 99.66 431263D | 1 0.01 99.67 600720A | 1 0.01 99.68 620904E | 1 0.01 99.69 623070L | 1 0.01 99.70 624338K | 1 0.01 99.71 624473D | 1 0.01 99.72 627835x | 1 0.01 99.73 628181v | 1 0.01 99.74 631121P | 1 0.01 99.75 632474F | 1 0.01 99.76 638337U | 1 0.01 99.77 668061N | 1 0.01 99.78 718397A | 1 0.01 99.79 723002L | 1 0.01 99.80 725393P | 1 0.01 99.81 725401E | 1 0.01 99.82 726861K | 1 0.01 99.83 787548A | 1 0.01 99.84 8888888 | 1 0.01 99.85 99999 | 1 0.01 99.86 9999999 | 14 0.14 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 22 Oct 2016