The Curve steepens.

Sorororry, more learning.
Way back here, I tried to compare "then"with "Now" daylight, usable by the PV Cells on the Roof. Since then Clicky's introduced me the the Mysteries of Opacity - SO - this is my next attempt of Then Vs. Now.  
By a totally unintended coincidence - it's exactly one Calendar month since that attempt.

I've done my best to coordinate the Axes; consequently the "long" Day in early/mid August was about twice the usable daylight length of a January AND generated a guessimetric 30% more Lecky per day.  More coincidence = Three consecutive, virtually cloudless days, both times.