Frequencies for not_hour variable in accident dataset :

Notificatio |
     n Time |
   EMS-Hour |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        298       60.94       60.94
         99 |        191       39.06      100.00
------------+-----------------------------------
      Total |        489      100.00

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