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

Speed Limit |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         59        0.59        0.59
         10 |          5        0.05        0.64
         15 |         32        0.32        0.96
         20 |         20        0.20        1.16
         25 |        694        6.94        8.10
         30 |        574        5.74       13.84
         35 |      1,363       13.63       27.47
         40 |        887        8.87       36.34
         45 |      1,172       11.72       48.06
         50 |        421        4.21       52.27
         55 |      4,002       40.02       92.29
         60 |          2        0.02       92.31
         65 |        630        6.30       98.61
         99 |        139        1.39      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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