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

Speed Limit |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         39        0.39        0.39
         10 |          6        0.06        0.45
         15 |         37        0.37        0.82
         20 |         14        0.14        0.96
         25 |        717        7.17        8.13
         30 |        614        6.14       14.27
         35 |      1,434       14.34       28.61
         40 |        875        8.75       37.36
         45 |      1,064       10.64       48.00
         50 |        458        4.58       52.58
         55 |      4,445       44.45       97.03
         99 |        297        2.97      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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