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

Speed Limit |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         67        0.67        0.67
         10 |          3        0.03        0.70
         15 |         25        0.25        0.95
         20 |         15        0.15        1.10
         25 |        756        7.56        8.66
         30 |        633        6.33       14.99
         35 |      1,429       14.29       29.28
         40 |        858        8.58       37.86
         42 |          1        0.01       37.87
         45 |      1,255       12.55       50.42
         50 |        413        4.13       54.55
         55 |      4,300       43.00       97.55
         70 |          1        0.01       97.56
         99 |        244        2.44      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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