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

SPEED LIMIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         33        0.33        0.33
          5 |          2        0.02        0.35
         10 |          5        0.05        0.40
         15 |         25        0.25        0.65
         20 |         14        0.14        0.79
         25 |        514        5.14        5.93
         30 |        441        4.41       10.34
         35 |      1,055       10.55       20.89
         40 |        881        8.81       29.70
         45 |      1,588       15.88       45.58
         50 |        472        4.72       50.30
         55 |      2,501       25.01       75.31
         60 |        215        2.15       77.46
         65 |      1,255       12.55       90.01
         70 |        572        5.72       95.73
         75 |        202        2.02       97.75
         85 |          1        0.01       97.76
         99 |        224        2.24      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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