The Omni Group's Lion Update Statssoftware update statistics document with Lion data:
Because we're nice folks who want to help the development community, we've decided to make the information we gather public (in aggregate form) so that you can also benefit from this knowledge.
Below you'll find statistical information about all collected configurations to date. The information is provided as-is. We're not going to tell you exactly how many individual users have submitted the information, nor can we place any guarantee on the accuracy of this information. Remember, this is not a poll of the Mac OS X community at large, just a subset of our customer base.
Looking at the data, you can see how OmniFocus (by far Omni Group's most popular app) shows a steep Lion usage increase in July (obviously), and a gradual growth throughout January 2012, whereas lesser known apps like OmniWeb have shown an initial decline in user adoption of the latest OS, then stable updates. Surprisingly, OmniOutliner users don't seem to upgrade to Lion much.