German Web Pagecount

For my project I am trying to estimate how big the German speaking web is. You would naturally say there are two measures for this. The first being the actual language and I am sure that some people would say that the domain (.de, .ch, .at) is also a good indicator. If the domain is really a good measure is a whole new post in it self. So now how do you actually find out how big the web is? I went and thought that the search engines could assist me in this and did some queries. I used Goog$e, Bing and Yahoo (No Yahoo is not Bing just yet). Looking at the numbers it is amazing on how different the various engines index the web. I am aware that these are really rough estimates but I wouldn't have assumed such a difference.