If you're talking about the overall level of informality, I think it's about 5% nationally. We, like the New Zealanders, do a very comprehensive survey after each election to work out whether those votes were deliberately informal or accidental. Our research shows that the vast majority are accidental. It's very clear when people deliberately leave all the boxes blank or write special messages for either the Electoral Commission or members of Parliament on the ballot paper, but that's a different thing.
On July 26th, 2016. See this statement in context.