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 |          4        0.04        0.05
         15 |         21        0.21        0.26
         20 |         27        0.27        0.53
         25 |        756        7.56        8.09
         30 |        331        3.31       11.40
         35 |      1,226       12.26       23.66
         40 |        624        6.24       29.90
         45 |        691        6.91       36.81
         50 |        405        4.05       40.86
         55 |      3,797       37.97       78.83
         99 |      2,117       21.17      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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