I know that there are a total of 71 secrets in the game, but finishing up my first play through the game I see I've missed some, and I don't know where to even begin to look as I start a 2nd game and go for the Seeker of Secrets achievement.
I'd like to know how many secrets are on each level, so as I play through the game again, I can have a better sense of which ones I might be missing and where I need to focus more effort on searching.
How many secrets are on each dungeon level?