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

SPEED LIMIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         36        0.36        0.36
          5 |          1        0.01        0.37
         10 |          2        0.02        0.39
         15 |         24        0.24        0.63
         20 |         17        0.17        0.80
         25 |        581        5.81        6.61
         30 |        511        5.11       11.72
         35 |      1,199       11.99       23.71
         40 |        908        9.08       32.79
         45 |      1,724       17.24       50.03
         50 |        474        4.74       54.77
         55 |      2,188       21.88       76.65
         60 |        183        1.83       78.48
         65 |      1,215       12.15       90.63
         70 |        587        5.87       96.50
         75 |        151        1.51       98.01
         80 |          1        0.01       98.02
         99 |        198        1.98      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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