[Air-L] youtube users statistics

Hello, Is anyone aware of articles, studies or reports detailing statistical information on the aggregate YouTube audience? Demographic info, good. Psychographic info, even better. Anything related to civic/political uses, fantastic. I'm aware of Youtube Insight, but the tool seems to be for specific users, not about the aggregate. I imagine what I'm asking for is quite elusive, but please do inform me of any possible leads. Thanks in advance, Muzammil