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

Speed Limit |      Freq.     Percent        Cum.
------------+-----------------------------------
          5 |          1        0.01        0.01
         10 |          3        0.03        0.04
         15 |         26        0.26        0.30
         20 |         31        0.31        0.61
         25 |        892        8.92        9.53
         30 |        386        3.86       13.39
         35 |      1,131       11.31       24.70
         40 |        460        4.60       29.30
         45 |        781        7.81       37.11
         50 |        420        4.20       41.31
         55 |      4,356       43.56       84.87
         99 |      1,513       15.13      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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