Frequencies for sp_limit variable in accident dataset :

Speed Limit |      Freq.     Percent        Cum.
------------+-----------------------------------
         10 |          2        0.41        0.41
         15 |          5        1.02        1.43
         20 |         11        2.25        3.68
         25 |         73       14.93       18.61
         30 |         26        5.32       23.93
         35 |        158       32.31       56.24
         40 |         59       12.07       68.30
         45 |        111       22.70       91.00
         50 |         23        4.70       95.71
         55 |         21        4.29      100.00
------------+-----------------------------------
      Total |        489      100.00

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