StatCounter's desktop and mobile stats show a consistent decline from 26.49% in June 2011 to 16.86% in May 2003.
StatCounter's desktop stats show a peak of 32.21% in November 2009 down to 19.76% last month.
The Clicky stats are similar, showing a peak of 33.43% in December 2009, down to 21.19% in May 2013.
And then there's W3Counter's data, which shows peaks of 32.3% between December 2009 and March 2010, down to 19.2% in May 2013.
Wikimedia's data, although not as recently updated, shows a peak of 30.96% in February 2010, down to 19.11% in October 2012.
The numbers you cite are quite different from these other sources, which are all relatively consistent, which in turn makes me suspicious of yours.
I think we have indeed seen Firefox go from approximately 30% share at the end of 2009 and beginning of 2010 down to less than 20% today. That's a pretty significant drop in just 3.5 years.
As for my negatively, like I said, the Mozilla crew has earned it. I know many others share this opinion, as well. The numbers above support that very strongly.
We were quite happy with Firefox up until Firefox 4. Before then, the focus was on usability, and providing a good browser. Since then, however, the priorities have clearly shifted, and the resulting product has declined in quality and usability quite severely. It's a bad situation, and I'm not going to pretend otherwise. Some people speak out, others just move to a different browser.
