title: Data on number of users of each version of Mac OS X?
body: <p>Is there publicly available data somewhere with estimates on the number of users of each Mac&nbsp;OS&nbsp;X version? Particularly for the major releases (10.6.* Snow Leopard, 10.5.* Leopard, ...)?</p>
  
  <p>I am writing a new application and am wondering whether it's still worth the effort of supporting pre-Leopard versions of Mac&nbsp;OS&nbsp;X, mostly Tiger. I am using <a href="http://sparkle.andymatuschak.org/" rel="noreferrer">Sparkle</a> with the option of tracking system profiles with every update check, but as the application is still in early 0.* releases the number of users so far is so small it's hardly statistically relevant. The application is built to support Tiger and up, but I have not yet seen a Tiger user in the system profiles yet.</p>
  
  <p>I realise there are some other factors at play too besides the number of users to decide whether to still support an older release. For example, I waited a long time to upgrade to Leopard myself, and at some point I got so used to seeing "requires at least Mac&nbsp;OS&nbsp;X 10.5" that I stopped looking for new applications altogether. I expect that's similar for anyone else still using Tiger.</p>
  
  <p>Still, would be nice to have the data. Also just out of curiosity ... anyone seen someone still using Cheetah lately? ;)</p>