10 Year Rolling Average Returns of Berkshire Hathaway

In doing my research to update the charts for my online classes (which you should take), I noticed that Warren Buffett never lost money until the two most recent stock market crashes; Dotcom and today's.

It then got me thinking, what has been the rolling average return of Berkshire Hathaway?

Pretty hard to make a buck when the whole country is tanking, isn't it Warren? Or perhaps a better question is;

"Precisely what assets do you buy or invest in while sitting on the decks of the Titanic?"