As home prices rise across the U.S., and wage increases fail to keep up, affordability continues to slip.

In fact, home prices are growing so much, a report in October from the Urban Institute shows some cities may even be growing close to becoming a housing bubble.

Now, the National Association of Realtors published a list on housing affordability, showing median home prices across U.S. metropolitan areas, according to an article by Tanza Loudenback for Business Insider.

The article shows the minimum salary required to qualify for a home in some of the most expensive metros, but assumes the buyer paid a 20% down payment. The study assumes a mortgage rate of 3.9% for all areas with the monthly principal and interest payment totaling 25% of income.

For comparison, the national average qualifying income to buy a home is $46,808, and the national median home price is $247,800. Here are the top seven most expensive cities in the U.S., and how much homebuyers need to earn in annual income to afford to buy a home.

7. Los Angeles-Long Beach-Glendale, California

Median home sale price: $541,200

Salary needed to buy a home: $104,516

6. Boulder, Colorado

Median home sale price: $546,400

Salary needed to buy a home: $103,212

5. San Diego-Carlsbad, California

Median home sale price: $610,000

Salary needed to buy a home: $115,226

4. Urban Honolulu, Hawaii

Median home sale price: $760,600

Salary needed to buy a home: $143,674

3. Anaheim-Santa Ana-Irvine, California

Median home sale price: $785,000

Salary needed to buy a home: $148,283

2. San Francisco-Oakland-Hayward, California

Median home sale price: $920,000

Salary needed to buy a home: $173,783

1. San Jose-Sunnyvale-Santa Clara, California

Median home sale price: $1,270,000

Salary needed to buy a home: $239,897