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

      FIRST |
ACCIDENT-YE |
         AR |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      5,524       55.24       55.24
       2001 |        650        6.50       61.74
       2002 |      1,509       15.09       76.83
       2003 |      1,256       12.56       89.39
       2004 |        496        4.96       94.35
       9999 |        493        4.93       99.28
          . |         72        0.72      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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