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

      FIRST |
ACCIDENT-YE |
         AR |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      5,364       53.64       53.64
       2002 |        608        6.08       59.72
       2003 |      1,456       14.56       74.28
       2004 |      1,342       13.42       87.70
       2005 |        595        5.95       93.65
       9999 |        572        5.72       99.37
          . |         63        0.63      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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