The government do reports on tourists constantly because after farming, it's our biggest industry.

https://www.stats.govt.nz/information-releases/international-visitor-arrivals-to-new-zealand-october-2018

I was only joking about the Aussies - they are our number one source of tourists - followed by China second and America third.

And ages - a full range from kids to grandparents. 25-43 is the top age range, but there is a pretty even spread.