Frequencies for first_yr variable in vehicle dataset :

      FIRST |
ACCIDENT-YE |
         AR |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        325       51.92       51.92
       2001 |         26        4.15       56.07
       2002 |        165       26.36       82.43
       2003 |         29        4.63       87.06
       2004 |         22        3.51       90.58
       9999 |         58        9.27       99.84
          . |          1        0.16      100.00
------------+-----------------------------------
      Total |        626      100.00

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