That now takes effect when tenants earn more than $250,000.

That means to secure a $2,000-a-month apartment, a tenant must earn at least $80,000 a year.

About 8,900 rent-stabilized tenants earning $175,000 or more pay less than $2,000 a month, the figures show.

Relatively few tenants earn enough to withstand big rent increases.

Under existing rules, if tenants on welfare earn money from jobs, they often have to pay part of that income as extra rent.

Most potential tenants earn well below the maximum limits.

To afford that, according to federal guidelines, a tenant should be earning $23.65 an hour - nearly five times the minimum wage.

In Westminster alone, more than 2,000 social tenants earn £50,000 a year or more, with around 200 on six figure salaries.

"The idea is to encourage landlords to seek a higher interest account, so both the landlord and the tenant would earn more."

It is not feasible for for-profit owners to operate housing where tenants earn, on average, less than $7,000 a year.