Frequencies for first 10,000 rows of sp_limit variable in accident dataset :

Speed Limit |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         65        0.65        0.65
         10 |          4        0.04        0.69
         15 |         30        0.30        0.99
         20 |         26        0.26        1.25
         25 |        745        7.45        8.70
         30 |        549        5.49       14.19
         35 |      1,351       13.51       27.70
         40 |        883        8.83       36.53
         45 |      1,141       11.41       47.94
         50 |        448        4.48       52.42
         55 |      4,085       40.85       93.27
         60 |          2        0.02       93.29
         65 |        539        5.39       98.68
         99 |        132        1.32      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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