The Midwest had the nation's highest proportion of homeowners and the best kept houses in 1985, the latest year for which detailed statistics are available, but the Northeast had the largest homes, according to data released this month by the Census Bureau.

The Midwest had the highest proportion of homeowners, 66.3 percent, in 1985, although that figure was declining as was the national average of 63.5 percent, according to the 1985 American Housing Survey for the United States, published by the Census Bureau.The survey is conducted every other year for the Deparment of Housing and Urban Development.

The South had the second highest proportion of ownership of occupied homes in 1985, 66.1 percent, followed by the Northeast, 60.6 percent, and the West, 58.7 percent.

The nation as a whole has suffered a loss in the proportion of homeowners due to skyrocketing housing prices in the 1980s, said Bill Hartnett, statistician for the bureau. Nationwide, the homeownership rate peaked in 1980 at 65.6 percent.

The West's homeownership rate, however, peaked in 1976 at 60.9 percent when housing costs went through the roof in the 1970s.

In the Northeast, homeownership peaked in 1983 at 61.5 percent, Hartnett said. The Midwest and the South followed the national trend and both peaked in 1980, at 69.8 and 68.7 percent, respectively.

In 1985, the Midwest had the smallest proportion of units with "severe physical problems," one percent, against a national average of 1.8 percent. The Midwest was followed by the West, 1.1 percent, the South, 2.1 percent, and the Northeast, 2.8 percent.

House age was associated with size, Hartnett said.

The statistics showed the median year for house construction in the Northeast was 1949. This region had the largest homes, with a median area of 2,061 square feet per occupied unit, 26 percent above the U.S. median of 1,636 square feet.