Under-representation in family violence statistics

I am still wading through the Families Commission 292 page Family Violence Statistics report released yesterday. Here are two graphs that speak for themselves. All offending is rising, but Maori offending is rising faster. I wonder if instead of asking why Maori are so over-represented, because that seems to cause offence and finger-pointing about finger-pointing, I should frame the question differently. Why are NZ European so under-represented in the family violence statistics?