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

   Rollover |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      7,923       79.23       79.23
          1 |        782        7.82       87.05
          2 |      1,295       12.95      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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