Well, at least those are the website statistics of my personal website of the past month. I have IE, Firefox and Safari installed as well. I uninstalled Chrome, as I really start to dislike Google policies lately, like forced pushed update installations without user consent, stealing and tracking all browsing activity by default if users don't disable it, etc.
Safari is a resource hog and slow. Firefox used to be, and to a large extent is still favourite, but I like Opera's lean and clean look as well, and seems at the moment the browser with the lowest footprint, both in terms of installation and processor power. It is fast. There are just a few glitches here and there with display of some websites. Don't know if these are disfunctionalities in Opera itself, or other browsers are simply more tolerant of bad (non conforming to standards) webpage design.