Firefox 1.5 - November 29, 2005
Firefox 2.0 - October 24, 2006
Firefox 3.0 - June 17, 2008
Firefox 3.5 - June 30, 2009
Firefox 3.6 - January 21, 2010
Firefox 4.0 - March 22, 2011
Firefox 5.0 - June 21, 2011
	
		
			
				wikipedia said:
			
		
	
	
		
		
			Future versions
A draft roadmap indicates that Mozilla hopes to release versions 6 and 7 in 2011 following the release of Firefox 5 in June 2011. These versions will be smaller incremental updates, primarily focusing on improving speed, stability and security.[71]
		
		
	 
See, Chrome had fun with the version numbers because they meant jack shit to them. Mozilla took nearly 7 years to get from version 1.0 to 4.0, and now they throw that way with "smaller incremental updates." Sorry, small updates shouldn't warrant a full version release, especially when it breaks addons.
I only use Firefox sparingly lately, I've switched to chrome quite a while ago, and I've had a better browsing experience because of it. I'd venture to say that I actually use Internet Explorer more often than firefox now.