last year

it's primarily looking at the last ten years (there's a link in the article you linked to explaining the methodology).

I don't think the site is biased it's just that this bankability system isn't great. If you're going to use it be very cautious of people tagged as "lead ensemble" figures in comic book movie team ups (e.g. Favreau is a "lead" of Endgame and Homecoming) and the people behind DC/Marvel universes are warped by this system seemingly because there's no way to treat "IP" as a 3rd source of value.

I think we'd really need to see under the hood to evaluate the claims being made. There appear to be a number of blindspots but how big are they for people not regularly doing massive interconnected franchise films?