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

SPEED LIMIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         58        0.58        0.58
          5 |          1        0.01        0.59
         10 |          3        0.03        0.62
         15 |         36        0.36        0.98
         20 |         26        0.26        1.24
         25 |        676        6.76        8.00
         30 |        569        5.69       13.69
         35 |      1,282       12.82       26.51
         40 |        887        8.87       35.38
         45 |      1,285       12.85       48.23
         50 |        415        4.15       52.38
         55 |      4,008       40.08       92.46
         60 |          3        0.03       92.49
         65 |        630        6.30       98.79
         99 |        121        1.21      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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