A request for Marauders+

If any of you ever have spare time and aren't doing anything, or even just while you're grinding... can you count how many hits it takes to charge energy to full?

I've been wondering this. I'm guessing somewhere around the range of 20-40, but if we could get an exact number that would be nice.

A confirmation that more monsters is proportionally faster would be helpful too.

Thanks in advance..