Frequencies for first 10,000 rows of sch_bus variable in accident dataset :

 School Bus |
    Related |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,976       99.76       99.76
          1 |         24        0.24      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Apr 2016