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

SPEED LIMIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         47        0.47        0.47
          5 |          1        0.01        0.48
         10 |          3        0.03        0.51
         15 |         29        0.29        0.80
         20 |         21        0.21        1.01
         25 |        600        6.00        7.01
         30 |        492        4.92       11.93
         35 |      1,154       11.54       23.47
         40 |        919        9.19       32.66
         45 |      1,734       17.34       50.00
         50 |        429        4.29       54.29
         55 |      2,350       23.50       77.79
         60 |        191        1.91       79.70
         65 |      1,185       11.85       91.55
         70 |        533        5.33       96.88
         75 |        160        1.60       98.48
         90 |          1        0.01       98.49
         95 |          1        0.01       98.50
         99 |        150        1.50      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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