Sure. This is the most informative public document I've found on the Google hiri...

Sure. This is the most informative public document I've found on the Google hiring process, it contains the 35% and 25% estimation:

The 0.5% (in fact less than 0.5%) comes from Google itself, from Don Dodge's blog:

I've researched this because I was on an onsite interview at Google on Tuesday and I am waiting for their answer right now...