140,500 --- 812 --- Auckland median household income (more than one person in average household)
My little table is just a general rule of thumb, but it was yearly salary and weekly rent / mortgages.
If someone is trying to aggressively pay down their mortgage before higher interest rates kick in, 30% is not a bad idea.
If you're trying to save for a deposit, 20% of gross income for rent would be better obviously.
Sorted has a nice website