I don't understand why National's is trying to get everyone to want tax cuts. And I don't understand how he can get away with this bullshit "12% of households pay 76% of net taxes" line.
"Net taxes" is not a real thing. These are the official tax statistics published by the IRD. "Net taxes" is not among them, nor should it be, because it's estimate of a bunch of arbitrary measures, put together for entirely political ends.
So, I've put together the IRD tax statistics from 2003-12 into this interactive data visualisation, to look at whether the top 10% pay a disproportionate amount of tax, and why.