This game uses Numbeo's mortgage-as-a-percentage-of-income figure by city.

• Higher values mean a larger share of income would go to a mortgage under the source assumptions.
• It is not a guarantee of what any one borrower pays, but it is a blunt city-level affordability alarm.
• The ratio moves with local incomes, prices, and interest assumptions all at once.

Plenty of cities sell the dream of ownership while invoicing it like a punishment.