Average annual household income is now a fraction under $100,000. But, according to the latest Housing Affordability Index, it?s enough to secure a loan to buy the typical Australian house.

According to the index published by the Commonwealth Bank and the Housing Industry Association, families need to earn $107,500 to qualify for a loan to buy the typical house, which now costs $437,000.

The index for the December quarter fell to its lowest level since the series was started in 1984, reflecting the November interest rate rise and strong growth in established house prices during the quarter.

The index shows that the median first home price rose from $431,000 to $437,000, interest rates rose from 7.7% to 7.95% and the qualifying income needed to get a loan for that average home went from $103,800 to $107,600.

But because average annual household income is $99,800, the Housing Affordability Index is 92.8 - down from 94.4 three months earlier and 106.9 two years ago.

An affordability index of 92.8 means that average incomes are only 92.8% of the required income to qualify for a loan to buy the typical house.