SALEM — Oregon’s population increased by more than 40,000 people over the last year, or 1%, according to an estimate from Portland State University’s Population Research Center.

Since 2010, the state has added more than 400,000 residents.

Still, this year has seen slower growth than in the recent past. Last year, Oregon’s population increased by 54,200 people. The year before that, the population grew by 64,750.

PSU’s research center said this slight slowdown in growth mirrors “the slowdown in employment growth.”

Morrow County had the largest percentage of growth with 6.7%. Boardman’s population went from 3,690 in 2018 to 4,490.

The growth in Umatilla County was marginal. The county finished 2018 with 80,765 residents and preliminary 2019 figures show the county with 81,160, a rate of 0.4%.

Growth in the county’s two largest cities was also on the upswing. Preliminary estimates show Pendleton with 16,985 residents, up from 16,810 in 2018. Hermiston’s preliminary numbers show it with 18,370, up from 18,200 residents in 2018.

The state’s aging population and a declining birth rate has also contributed to the slowdown. In its report, PSU said Oregon’s births outnumbered deaths in the past year by less than 6,000.

A continuing trend is that the state’s growth relies more on people moving to Oregon, rather than new residents being born here.

In this past year, the number of people moving to the state has been the main factor of population growth, accounting for 86% of new residents.

The Portland metro area accounted for nearly half of the state’s growth from 2018 to 2019. Multnomah and Washington counties each added more than 7,000 new residents, PSU said, and Clackamas County added almost 4,000.

Other counties with a large number of new residents include Deschutes, with more than 4,000, and Lane and Marion, both with about 3,700 new residents.

Crook County also saw a large growth rate with 3.2%.