Last year housing starts in this country exceeded, ever so slightly, the 2 million level for the fourth time in a decade.

The estimated 2,007,000 housing units begun last year would also slightly exceed the 1,987,000 total in 1977 and would rebut several housing indutry forecasts of a year ago that 1978 starts would decline about 10 percent.

Official 1978 housing statistics will be released later this month by the federal government. William Young of the statistical section of the National Association of Home Builders said that the expected total was the result of an unexpected strong performance during the year in the single-family housing field.

Starts on single-family houses are expected to total 1.4 million for the year, just slightly below the record set in 1977. Starts on multi-family housing, sluggish since 1973, are expected to reach 578,800, slightly more than in 1977.

Young added that the recently revised NAHB forecast for housing starts in 1979 points to a 22 percent turndown, ot a total of 1.6 million, with most of the decline being in single housing starts. Current high financing costs have made 1979 forecasts to be less optimistic.

Total housing starts hit a record 2.35 million in 1972, up from more than 2 million in 1971. The total fell back to 2,045,000 in 1973. But both 1974 and 1975 were exceptionally lean for housing starts: the levels fell to 1.3 and 1.1 million before rebounding to 1.5 million in 1976.

The somewhat unexpected strength of the new housing market last year was matched by the level of resales of existing houses across the land. Kenneth Kerin, reserach director of the National Association of Realtors, said that final statistics for all residential resales in 1978 are expected to hit a record 3.9 million level for a total dollar volume of $220 billion. In 1970, total resales were only 1.6 million and the 3 million level in unit sales was reached for the first time in 1976.

Kerin said that the impetus of the resale market is expected to carry through into 1979, despite rising mortgage interest rates. Rates are now higher than 10 percent in most areas.

Kerin prdicted that more than 4 million existing houses would be resold this year. He contended that the so-called psychological barrier of high rates to buying has not been encountered because of the continuing strong interest in ownership among young Americans.

Statistics show that the median price of a new house rose from $23.400 in 1970 to $48,700 in 1977 and hit $58,400 in Cotober last year. Resale house prices were at a $23,000 median in 1970 and rose to $48,800 in 19789

In the Washington area, starts are expected to total 21,149 for 1978, slightly below the 1977 level. The NAHB forecast for this area is 17,000 starts in 1979, considerably below the 1977 and 1978 levels and far below the 42,183 mark of 1972. In the doldrums of 1975 only 9,554 housing starts were made in this area. Builders generally are more cautious now about starting new houses in any numbers without deposits from prospective buyers.

Area starts of single-family houses peaked at 25,993 in 1972 and rebounded to 16,503 in 1977 and are expected to hit 15,490 in 1978. Multi-family starts peaked at 18,791 in 1973 but fell to 2,324 in 1975. Apartment starts were 6,518 in 1977 and are likely to total 5,659 for 1978. The forecast for 1979 in 5,000 apartment starts in this area.

On the resale front, the Prince George's Board of Realtors reported that both listings and sales have doubled since 1973, when there were 10,042 listings and 5,259 sales. For 1978, there are expected to be 19,341 listings and 11,365 sales recorded through the multiple listing service. Board executive Paul Fowler said the average price paid for a single-family house last November was $54,400; the average condominium resale price was $33,800.

Hans Nestler of the Montgomery County Board of Realtorsthere said that listings increased from 10,828 in 1973 to 17,300 in 1978, while sales increased from 5,530 to an estimated 10,000 in 1978. He siad that the average price of resale houses in November was $79,800.

Statistics for the Northern Virginia Board of Realtors, supplied by executive assistant Aubrey Gaskins (who will become top executive of the Virginia Beach Board of Realtors on Feb. 1), showed that listings totaled 37,415 and sales hit 21,683 for the first eleven months of 1978, compared with 36,903 listings and 16,947 sales in the same period in 1977. He said that the average selling price was $73,800 in 1978, up from $70,200 in 1977.

The Washington Board of Realtors, which adopted a multiple listing service last March, reported that it now has 885 listings in the District for single-family houses averaging $97,297, a figure that reflects the generally more expensive houses listed by the service.

The D.C. board also has 207 condominium and coop apartment listings at an average of $59,525. Altogether, 114 realtor firms with 2,500 agents now are participating in he Washington multiple listing program.

With the upsurge in inflation, building and reselling of houses in the past two years, mortgage indebtedness has also increased markedly.