And since then, that missing episode has been released, and BBC America has funded the animation of a completely missing serial to give us another entire release from the Troughton era.
/yeah, the disc is due out at the end of the month as I type, but it's out in the wild.
The best way to do Doctor Who is "All 139 surviving serials (of 159), 1963-1989", TV Movie (1996)
I think that's roughly accurate... I did a quick count of the Hartnell and Troughton DVDs and that added up to 30 serials released. There were 50 serials between those two eras. So do the math...