Frequencies for first 10,000 rows of veh_no variable in violatn dataset :

    Vehicle |
     Number |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      6,696       66.96       66.96
          2 |      2,572       25.72       92.68
          3 |        499        4.99       97.67
          4 |        137        1.37       99.04
          5 |         51        0.51       99.55
          6 |         16        0.16       99.71
          7 |          7        0.07       99.78
          8 |          5        0.05       99.83
          9 |          3        0.03       99.86
         10 |          3        0.03       99.89
         11 |          3        0.03       99.92
         12 |          3        0.03       99.95
         13 |          2        0.02       99.97
         14 |          2        0.02       99.99
         15 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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