The wealthiest racing drivers in history

I am including any assets owned by the individual racing driver (i.e. properties/dealerships etc.) as well as businesses and liquid cash, in my definition of “wealthy”.

I know from the Forbes 100 celebrity list 2004 that Micheal Schumacher is worth around $80 million per year, followed by Dale Earnhardt Jr. at around $20.2 million and Jeff Gordon at $19.7 million.

From here it looks like Eddie Irvine isn’t doing too bad at all (shrewd property investments have earned him £153 million - that’s probably well in excess of $200 million).

But maybe Piquet or Senna earned more. Who in thier heyday earned the most money, and who is the most wealthiest racing driver of all time?

A top ten list would be brilliant.