Frequencies for a_imp1 variable in veh_aux dataset :

     Intial |
     Impact |
      Point |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         35        4.87        4.87
          2 |        510       71.03       75.91
          3 |         62        8.64       84.54
          4 |         46        6.41       90.95
          5 |         63        8.77       99.72
          6 |          2        0.28      100.00
------------+-----------------------------------
      Total |        718      100.00

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