Yeah old news -
Not sure what kind of stats you folks are seeing, but here's a few niches and the % of "not provided" search terms I got:
Legal/Law Firm - 24.9% Blocked
Rock Magazine - 21.8 % Blocked
Construction - 24% Blocked
Software Company - 25.2% Blocked
The face that I can't dig into these blocked terms is killing me, but not much I can do about it - still enough data to make valid decisions based on the rest of the keywords though.
I think it's a ridiculous move by Google. More than SEO's use keyword data in their analyses.