Deschutes County was the fastest-growing county in the state during the last year, according to the latest population estimates from Portland State University.

Countywide, the population grew 2.4 percent from July 1, 2013, to July 1, 2014, according to estimates released Nov. 18 by PSU’s Population Research Center. Deschutes County added 3,875 people, bringing its total population to an estimated 166,400.

Hood River County recorded the second-highest growth rate, 1.9 percent, during the period. The county, which borders the Columbia River, added 435 people for a total estimated population of 23,730 as of July 1, according to PSU.

The Nov. 18 estimates are preliminary. PSU expects to certify final population estimates by Dec. 15, according to a summary report.

Statewide, Oregon added 43,545 people , or 1.1 percent. Oregon’s total population estimate: nearly 3.4 million.

Staff at the Population Research Center attributed about 74 percent of the state’s population growth in the last year to people moving into Oregon. Natural increase — the number of deaths minus the number of births — accounted for 26 percent, according to the summary.

During the 1990s and up to 2009, people migrating to Oregon from elsewhere drove the state’s population growth. However, during the recession, when fewer people moved to the state, natural increase accounted more for population growth, according to PSU.

In sheer numbers, the counties around Portland — Washington, Multnomah and Clackamas — saw the greatest increases in population during the last year, adding 24,165 people combined. Washington and Multnomah counties added 9,475 and 9,245 people respectively.

— Reporter: 541-383-0360,

tdoran@bendbulletin.com

Editor’s note: This story has been corrected. In the original version, the numerals in the percentage increase of Deschutes County’s population were transposed.

The Bulletin regrets the error.