Firefox 3.5 was downloaded more than 5 million times in 24 hours, but this is still 3 million less than the 8 million downloads when Firefox 3 was released.
With the release of Firefox 3.5, Mozilla have provided real time Firefox download information. Current downloads totals for 3.5 are nearing 9 million in just 2 days.
Overall Firefox downloads are estimated to be over 900 million.