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

   Rollover |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      8,134       81.34       81.34
          1 |        625        6.25       87.59
          2 |      1,241       12.41      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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