Frequencies for first 10,000 rows of first_yr variable in vehicle dataset :

      First |
Accident,et |
     c-Year |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,182       41.82       41.82
         75 |      1,408       14.08       55.90
         76 |      1,829       18.29       74.19
         77 |      1,322       13.22       87.41
         78 |        458        4.58       91.99
         99 |        801        8.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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