Home Affordability at 14-Year High : Real estate: Declining mortgage rates and housing prices are cited by a Realtor group.

A combination of declining mortgage interest rates and housing prices made homes more affordable for the average American family in September than they had been in 14 years, the National Assn. of Realtors said Thursday.

Its housing affordability index was 116.1, up from a revised 111.2 in August. It was the largest monthly gain since record keeping began in 1971 and the highest since May, 1977, when it measured 118.6. In September of 1990 it was 110.2.

The index measures the ability of a family earning the median national income to buy a home at the median price.

Families earning the national median income of $36,361 a year had 116.1% of the income needed to afford a conventional loan.

Meanwhile, the national median home price fell $2,400 to $99,800 from August, although it was still $5,400 above September, 1990.

The national median income was up $112 from the previous month and $1,293 above year-ago levels, the Realtors said. The interest rate used to calculate the index was 9.17%, down from 9.36% in August and 10.0% in September, 1990.

A Northeast family earning $40,049 had 93.0% of the income needed to buy a house priced at $136,900. In the West, a family earning $37,788 had 83.3% of the income needed to buy a $144,000 home.

A Midwest family earning $37,491 had 156.6% of the income needed to buy a $76,300 house. A family in the South earning $32,703 had 113.7% of the income needed to buy a $92,000 home.