Although I hate to post it Net Applications has bettor browser statistics then w3schools because they take there data from a larger sampling of websites then w3schools which only shows the browsers of people who are visiting there site. Because w3schools is targeted towards coders and web developers the statistics are skewed towards better browsers.
(a) Market share percentage of internet explorer users there is by version (2011 data and 2010 data)
(b) This market share by browser to be sub-divided by the different versions of the relevant browser.
(b) A similar breakdown for other major browsers (firefox, safari and chome mainly).
Generally speaking "general data" isn't particularly useful, the browser makeup of visitors varies vastly depending on your target user-base. For example for a b2b website you generally have much higher usage of old IE versions than most b2c sites.
What you really need to look at is the user-base for your particular site as that's what really matters. If you have Google Analytics installed that will give you the data you want.