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

SPEED LIMIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         50        0.50        0.50
          5 |          1        0.01        0.51
         15 |         25        0.25        0.76
         20 |         12        0.12        0.88
         25 |        593        5.93        6.81
         30 |        577        5.77       12.58
         35 |      1,229       12.29       24.87
         40 |        872        8.72       33.59
         45 |      1,419       14.19       47.78
         50 |        457        4.57       52.35
         55 |      3,939       39.39       91.74
         60 |          2        0.02       91.76
         65 |        641        6.41       98.17
         99 |        183        1.83      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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