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

SPEED LIMIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         31        0.31        0.31
          5 |          2        0.02        0.33
         10 |          4        0.04        0.37
         15 |         19        0.19        0.56
         20 |         17        0.17        0.73
         25 |        549        5.49        6.22
         30 |        443        4.43       10.65
         35 |        995        9.95       20.60
         40 |        871        8.71       29.31
         45 |      1,675       16.75       46.06
         50 |        491        4.91       50.97
         55 |      2,402       24.02       74.99
         60 |        177        1.77       76.76
         65 |      1,225       12.25       89.01
         70 |        652        6.52       95.53
         75 |        215        2.15       97.68
         90 |          1        0.01       97.69
         95 |          1        0.01       97.70
         99 |        230        2.30      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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