Fewer Americans are seeking new homes in their current communities, but the number relocating across county and state lines is still great, a new Census report shows.

The total number of movers slipped from just over 45 million in 1984-85 to about 42 million in 1985-86, the bureau said Tuesday, as people scaled back from a burst of buying that marked the decline in mortgage interest rates.All of the drop came in moves within the same county, which fell from 30.1 million to 26.4 million, the study showed.

At the same time moves to another county in the same state rose from 7.9 to 8.6 million while interstate moves remained at about 6.9 million in each of the years.

Overall, 18.6 percent of Americans age 1 and over relocated between March 1985 and March 1986, down from 20.2 percent the preceding year, the report said.

Kristin A. Hansen, an analyst in the bureau's Population Division, explained that falling interest rates released a pent-up demand for new homes in the 1984-85 year, but in 1985-86 the rate of movement slipped back.

The figures are the most recent detailed statistics on mobility available. However, data collected by the departments of Commerce and Housing and Urban Development indicate that continued low interest rates helped spur strong sales of both new and existing homes last year.

Mobility fell to all-time lows early in this decade, dropping to 16.6 percent in 1982-83. Ms. Hansen said many people delayed moves because of high interest rates, but relocated later when the rates came down.

Here is a rundown of the overall share of Americans aged 1 and over who moved over one-year periods. The sample is limited to those over age 1 because mobility is judged by comparison of where people lived a year earlier.

Year Rate

1985-86 18.6

1984-85 20.2

1983-84 17.2

1982-83 16.6

1981-82 17.0

1980-81 17.2

1970-71 17.9

1960-61 20.0

1950-51 20.9