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

   rollover |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      7,777       77.77       77.77
          1 |        792        7.92       85.69
          2 |      1,431       14.31      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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