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

   rollover |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      7,871       78.71       78.71
          1 |        778        7.78       86.49
          2 |      1,351       13.51      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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