Frequencies for first 10,000 rows of rail variable in accident dataset : Rail Grade | Crossing | Identifier | Freq. Percent Cum. ------------+----------------------------------- 0000000 | 9,952 99.52 99.52 003324M | 1 0.01 99.53 025017A | 1 0.01 99.54 057344Y | 1 0.01 99.55 078357H | 1 0.01 99.56 167028E | 1 0.01 99.57 173908X | 1 0.01 99.58 174107H | 1 0.01 99.59 271957 | 1 0.01 99.60 272405C | 1 0.01 99.61 289067H | 1 0.01 99.62 289545F | 1 0.01 99.63 289680Y | 1 0.01 99.64 295148W | 1 0.01 99.65 330499R | 1 0.01 99.66 351232H | 1 0.01 99.67 351461C | 1 0.01 99.68 353704J | 1 0.01 99.69 372350T | 1 0.01 99.70 542152T | 1 0.01 99.71 546494G | 1 0.01 99.72 608831U | 1 0.01 99.73 620288V | 1 0.01 99.74 628074F | 1 0.01 99.75 628138P | 1 0.01 99.76 628160C | 1 0.01 99.77 637621H | 1 0.01 99.78 637922D | 1 0.01 99.79 665944D | 1 0.01 99.80 668069T | 1 0.01 99.81 723198H | 2 0.02 99.83 727760C | 1 0.01 99.84 733227T | 1 0.01 99.85 741362G | 1 0.01 99.86 741713D | 1 0.01 99.87 746903y | 1 0.01 99.88 7878384 | 1 0.01 99.89 787838H | 1 0.01 99.90 804347G | 1 0.01 99.91 805473E | 1 0.01 99.92 831210J | 1 0.01 99.93 867232L | 1 0.01 99.94 8888888 | 1 0.01 99.95 9999999 | 5 0.05 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 18 Apr 2016