We guessed respectively 25%, 50%, 75% (my guess).
Based on some very, very, very fuzzy sampling, they estimated it was somewhere around 50%.
Any guess yourself? Are you a Rails dev?
While Rails certainly did a huge amount to make the language popular, there's lots of things Ruby is good at aside from concatenating snippets of HTML.
Actually, that being said, while maybe 90% of personal Ruby projects don't use Rails, a good half use ActiveRecord in some capacity. I wonder how much that makes it a Rails project, by some reasonable definition.
And indirectly by many more who use chef
Thankfully rubyconf explicitly says that it's not the place for rails-focused talks, which results in a lot of great discussion on other aspects + usages of the language. :)