Earlier quoted context omitted.
Mozilla has publicly stated that they make at least $300 million per year from Google (as of 2011) [1]. Although there are reports that this is closer to $1 billion per year now (including all search-related revenues). [1] http://en.wikipedia.org/wiki/Mozilla_Foundation#Financing
Where are those $1 billion reports from? That's the first I've heard of a number anything like that large. Firefox's market share hasn't tripled recently, and the current deal with Google is the same one that started in 2011, so it sounds unlikely to me.
$300MM is still a giant number.