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

   rollover |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      7,968       79.68       79.68
          1 |        704        7.04       86.72
          2 |      1,328       13.28      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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