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

SPEED LIMIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         32        0.32        0.32
          5 |          5        0.05        0.37
         10 |          4        0.04        0.41
         15 |         17        0.17        0.58
         20 |         19        0.19        0.77
         25 |        561        5.61        6.38
         30 |        445        4.45       10.83
         35 |      1,086       10.86       21.69
         40 |        898        8.98       30.67
         45 |      1,613       16.13       46.80
         50 |        465        4.65       51.45
         55 |      2,367       23.67       75.12
         60 |        216        2.16       77.28
         65 |      1,223       12.23       89.51
         70 |        596        5.96       95.47
         75 |        209        2.09       97.56
         90 |          1        0.01       97.57
         99 |        243        2.43      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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