These number are very different than that shown by StatCounter [1] and Wikipedia [2]. If you look at Wikipedia's comparisons, they compare data from many sources. NetApplications (the dataset used by this article) is by far the one source that differs greatly from the rest of the data.
This likely has to do with the types of audiences that visit the sites they monitor, so the data should be taken with a grain of salt.
[1] http://gs.statcounter.com/ [2] http://en.wikipedia.org/wiki/Usage_share_of_web_browsers