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

SPEED LIMIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         54        0.54        0.54
          5 |          1        0.01        0.55
         10 |          3        0.03        0.58
         15 |         26        0.26        0.84
         20 |         16        0.16        1.00
         25 |        587        5.87        6.87
         30 |        587        5.87       12.74
         35 |      1,273       12.73       25.47
         40 |        825        8.25       33.72
         45 |      1,368       13.68       47.40
         50 |        444        4.44       51.84
         55 |      3,984       39.84       91.68
         60 |          3        0.03       91.71
         65 |        678        6.78       98.49
         99 |        151        1.51      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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