As most of you probably know, Internet Explorer is the king of web browers, but this hasn't been the case since the start the World Wide Web... At the begging of the WWW, the king browser was Mosaic which was avaiable before any other browser, but this quickly changed around the mid of 1990's (mainly 1994, 1995 and 1996), when the most used browser was Netscape navigator (taking around 80% of the browsers usage) and IE was way lacking behind with around 10%. With time, this also changed...

In 1997, the figures were closer with around 60% for Netscape and 30% for IE and evetually Mosiac was loosing more figures. At the end of the 90s, the war was furious and both browers had similar figures with around 45%!
During the first 5 years of the next decade, IE with the king of browers and continued on gaining figures until reaching 90% of the total web browsers usage in early 2006. This domination of the market changed when FireFox was launched and it quickly gained 10% of the market in very few months and it continues to grow till now.
Now, these figures are as follows (according to TheCounter.com taken from Wikipedia.org):
IE: 81.63%
Netscape Navigator: 0.06% (all birds fall down eventually!)
FireFox: 13.49%
Opera: 0.66% (my personal favorite, but having a very low usage!!)
Safari: 3.00%