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

   PREVIOUS |
  ACCIDENTS |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      8,112       81.12       81.12
          1 |        955        9.55       90.67
          2 |        118        1.18       91.85
          3 |         24        0.24       92.09
          4 |          6        0.06       92.15
          6 |          1        0.01       92.16
         98 |        333        3.33       95.49
         99 |        410        4.10       99.59
          . |         41        0.41      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Apr 2016