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

Speed Limit |      Freq.     Percent        Cum.
------------+-----------------------------------
          5 |          3        0.03        0.03
         10 |          2        0.02        0.05
         15 |         31        0.31        0.36
         20 |         40        0.40        0.76
         25 |        882        8.82        9.58
         30 |        410        4.10       13.68
         35 |      1,246       12.46       26.14
         40 |        507        5.07       31.21
         45 |        883        8.83       40.04
         50 |        394        3.94       43.98
         55 |      4,267       42.67       86.65
         99 |      1,335       13.35      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Apr 2016