WebAPI to find account age?

I need a way to get a user's account age (Days since the account was made, not the actual person's birth date)

Yes, I need an actual WebAPI, the Player.AccountAge will do me no good, I'm trying to access this from a non-roblox-script place, but I can't find this anywhere, including the http://wiki.roblox.com/index.php?title=Web_APIs website.

Does anyone know how to do this, or even if it's just not possible? Thanks in advance!