I'm only one person, and not "most", and I don't want to share my latest data for commercial reasons but here's my open and click rates for all of my campaigns in September straight from the MailChimp's mouth: http://no.gd/openrates.jpg - these went out to a total of around 78k subscribers (software developers, specifically) each week.
Are most people lying though? I'm not so sure but the real proof of the pudding is in how much traffic they drive to you if you're in their newsletter somehow.