Average investment property rental yields..
Gross Rental Yields on Investment Property (Apartments)
6.09% New Zealand
Source: www.globalpropertyguide.com 2014 rates
However, when looking at the United States:
A New York, Lower Manhattan Apartment, is shown as 3.07% yield
whilst a Miami Condominiums is shown as high as a 10.27% yield.
That source shows the top two, and the bottom two, Rental Yield countries as:
15.1 - 676,661