Improvement formula

Hi

I currently have the dataset below

The purpose of the data is to show whether the efficiency is improving over the weeks.

Please can you help me understand if there is a mathematical formula I can use to show this?

Week 1: 10 bottles took 01.00 to load
Week 2 18 bottles took 01:25 to load
Week 3: 9 bottles 00.45 to load
Week 4: 5 bottles 00:15 to load
Week 5: 20 bottles took 01:30 to load

Time is expressed in hh:mm format.

Thanks