Charting Times of Day on Line Chart

[Danny318]

I want to show improvement, from last year to this year, on average delivery times on a line chart. How do I set up the chart axis, etc.? Thank you!
Last Year This Year
Jan 9:30:00 AM 7:30:00 AM
Feb 9:30:00 AM 7:30:00 AM
Mar 9:30:00 AM 7:30:00 AM
Apr 8:30:00 AM 7:30:00 AM
May 8:30:00 AM 7:30:00 AM
Jun 8:30:00 AM 6:30:00 AM
Jul 8:30:00 AM 6:30:00 AM
Aug 8:30:00 AM 5:30:00 AM
Sep 8:30:00 AM 5:30:00 AM
Oct 8:30:00 AM 5:30:00 AM
Nov 8:30:00 AM 5:30:00 AM
Dec 8:30:00 AM 5:30:00 AM

 

[PaddyD]

Given the data, what is your definition of 'improvement'? Is it simply (old time) - (new time) ?

 

[Jon Peltier]

I just plotted the two series of times vs the column of months. So I selected the range at left below (with top left cell blank) and inserted a line chart. The result was the top chart.

I formatted the vertical axis with the minimum = 0, maximum = 0.5 (because a day goes from 0 to 1, and noon is 0.5). I needed a major unit of 2:00:00, but Excel didn't accept that as an entry. but 2:00:00 = 2/24 = 0.0833333333, so I typed that into the box for major unit. I also changed the number format of the axis labels to h:mm AM/PM, because we don't need all of those extraneous digits; you could even go as far as h AM/PM. These changes led to the bottom chart.