Chart by date
 

I have a list of CFR numbers and the date & times that they have been used. CFR's are vehicle #'s if you are curious.

I want to chart (bar) by date the total time (CFR's combined) usage for each day.

Example:
Date CFR Time Out Time in TTL Time
May 1, 2015 1139 09:00 09:40 00:40
May 1, 2015 1138 09:55 10:25 00:30
May 1, 2015 1955 13:35 14:35 01:00
May 2, 2015 1954 08:00 Unknown
May 2, 2015 1139 08:55 12:25 03:30
May 7, 2015 1139 08:00 10:10 02:10
May 7, 2015 1955 09:20 09:34 00:14
May 7, 2015 1139 11:10 14:35 03:25
May 7, 2015 1954 13:30 14:10 00:40
May 7, 2015 1955 14:20 14:55 00:35
May 8, 2015 1954 08:10 10:25 02:15
May 8, 2015 1955 08:15 09:15 01:00
May 8, 2015 1138 08:25 Unknown
May 8, 2015 1139 08:30 09:10 00:40
May 8, 2015 1955 10:00 10:25 00:25
May 8, 2015 1955 10:30 Unknown

I want the chart to show me for each date what the total amount of usage has been. The actual CFR # doesn't matter, just the TTL Time by date.

So:
on May 1st, the total time 02:10
on May 2nd, the total time 03:30 (Unknown is to be ignored because someone forgot to put the "time in" in the log.)
on May 7th, the total time 07:04
Etc

Thank you in advance for your help on this. I am stumped.