Frequencies for cl_tway variable in accident dataset :

      Class |
 Trafficway |      Freq.     Percent        Cum.
------------+-----------------------------------
          3 |          2        0.41        0.41
          4 |        247       50.51       50.92
          5 |         54       11.04       61.96
          6 |         92       18.81       80.78
          7 |         82       16.77       97.55
          8 |         12        2.45      100.00
------------+-----------------------------------
      Total |        489      100.00

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