Thanks for your question. However we ask that you please ask questions on http://answers.ros.org following our support guidelines: http://wiki.ros.org/Support
ROS Discourse is for news and general interest discussions. ROS Answers provides a forum which can be filtered by tags to make sure the relevant people can find and/or answer the question, and not overload everyone with hundreds of posts.
But since I’m replying anyway, the ROS Metrics reports are the best source of numbers about the ROS community.