Gray vs Grey

To be quite honest I was having trouble thinking of things to write about and this just kind of popped into my head. TLDR; grAy = America, grEy = England or gray is a color and grey is a colour

Apparently they both have origins in the Old English grǽg but gray started to become the preferred spelling in American English around the 1820s. Somewhat interestingly the word greyhound is always spelled with the letter e and the unit of absorbed radiation dose of ionizing radiation is spelled with an a.

Also apparently the spelling gray was promoted by English lexicographers but grey became commonly accepted anyway. At around the same time in the US the 1867 and 1897 Webster's dictionaries include grey but have it refer to gray. What can we conclude from this? I have no idea. However the Google Ngram Viewer is kind of cool.