Frequencies for tra_cont variable in accident dataset :

    Traffic |
    Control |
     Device |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        488       85.46       85.46
          1 |          1        0.18       85.64
          2 |         19        3.33       88.97
          3 |         12        2.10       91.07
          4 |          1        0.18       91.24
          9 |          1        0.18       91.42
         20 |          5        0.88       92.29
         28 |          3        0.53       92.82
         40 |         35        6.13       98.95
         50 |          6        1.05      100.00
------------+-----------------------------------
      Total |        571      100.00

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