Frequencies for not_hour variable in accident dataset :

Notificatio |
     n Time |
   EMS-Hour |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        409       84.16       84.16
          1 |          1        0.21       84.36
         99 |         76       15.64      100.00
------------+-----------------------------------
      Total |        486      100.00

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