The wasted vote came third in 2008
Thanks to NZ First not getting a seat or over 5% but getting more than 88,000 votes, the wasted vote was bigger than the Green vote. The wasted vote was third this year - and that's the first time it has been ranked so high. More than 6.5% of the vote (137,472) was wasted, and had there not been a 5% threshold that would have gone down to 1.28% (26,983).
The wasted voted is vote for a party that does not get 5% or an electorate seat.
So you can see how important it is for a minor party to win an electorate seat and what influence a 5% threshold has. Since 2000 just two minor parties have got both at least one seat and more than 5% of the vote in the same election. That's all.
Interestingly NZ First got more votes in 2008 than in 2002, where it got 4.26% of the vote and four seats – it got 4.21% this year. Also Destiny got more in 2005 than Kiwi got this year. Destiny is now the Family Party. The Family Party got well under half what Destiny got in 2005.
If I get some more time to do some more numbers I'll add to this.