Frequencies for first 10,000 rows of prev_acc variable in vehicle dataset :

   previous |
   recorded |
    crashes |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      8,249       82.49       82.49
          1 |        750        7.50       89.99
          2 |         98        0.98       90.97
          3 |         13        0.13       91.10
          4 |          5        0.05       91.15
          5 |          2        0.02       91.17
          6 |          1        0.01       91.18
         98 |        439        4.39       95.57
         99 |        377        3.77       99.34
        998 |         66        0.66      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Oct 2016