http://deadline.com/2015/03/going-clear-clocks-1-652-million-viewers-in-hbo-premiere-1201402423/
Going Clear: Scientology and the Prison of Belief, Alex Gibney's two-hour exposé on the Church of Scientology, nabbed nearly 1.7 million viewers during its premiere telecast. And while that number is sure to grow once HBO-Go plays, encores and DVR views are taken into account, it already represents the network's most watched doc premiere since Spike Lee's four-part When the Levees Broke aired in 2006. (The Hurricane Katrina feature nabbed 1.75 million viewers.)
It should be noted that Going Clear also comes shy of HBO's 2013 Beyonce doc Beyonce: Life Is but a Dream (1.8 million viewers for the premiere), though that project was, essentially, a concert special.