Not exactly, but it was about 30% yes IIRC. At the time the rule was that a vote not cast counted as a no vote, so there's no way to distinguish between no voters and apathy on that vote.

I believe the rule was subsequently changed, so as I understand it in any such election today you only need a majority of the CAST ballots, so actually it would be easier to pull off today than in 2006 (apathy doesn't count as a no vote).