Good news on physical child abuse statistics?

I was prompted to check the latest physical child abuse statistics when I heard Deborah Coddington (standing in for John Tamihere on Radio Live) say that the anti-smacking legislation is working. No disrespect to Deborah but I immediately wondered what she bases that on.

At best it could be claimed that the anti-smacking legislation has lowered the projection, but the trend it is still upward.