How do I take a percentage of total time over a 7 day period when time exceeds 24:00 hrs?

I have attached a screenshot of what I am working with and attempting to accomplish.

For 'Tank Usage over 7 Days' I have calculated average time & average minutes wherein average time is by function =AVERAGE(A1, B1, etc.) in the format [hh]:mm and average minutes is by function =(A1)*24*60 in the format General.

Then I took totals for all tanks using the corresponding cells, but what is the formula to turn this data into percentages by average % of each tank, and by total % of each tank over a 7 day period when time exceeds 24 hours?

Thanks.