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

SPEED LIMIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         34        0.34        0.34
         10 |          6        0.06        0.40
         15 |         17        0.17        0.57
         20 |         23        0.23        0.80
         25 |        580        5.80        6.60
         30 |        494        4.94       11.54
         35 |      1,216       12.16       23.70
         40 |        871        8.71       32.41
         45 |      1,622       16.22       48.63
         50 |        442        4.42       53.05
         55 |      2,762       27.62       80.67
         60 |         89        0.89       81.56
         65 |        923        9.23       90.79
         70 |        560        5.60       96.39
         75 |        145        1.45       97.84
         99 |        216        2.16      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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