The most expensive housing in the state is generally the state’s most-populated counties, which are along the Interstate 5 corridor.

Oregon grew by more than 400,000 people during the first decade of this century, and nearly half of the growth was concentrated in Deschutes, Multnomah and Washington counties.

Population grew in all regions of Oregon between 2000 and 2010, and the proportion of Oregonians living in the three-county metropolitan Portland region inched up to nearly 43 percent, according to newly released U.S. Census Bureau data.Central Oregon grew by 30.5 percent during the decade — the fastest growth rate of any region of the state.

The number of college-educated Oregonians grew steadily during the past two decades — especially in Central Oregon — but there were significant regional disparities across the state, census data show.

Local tracts with the highest educational attainment — where upward of 75 percent of residents age 25 and older had a bachelor’s degree or higher — were exclusively on Portland’s west side, according to new U.S. Census Bureau data.

An estimated 30 percent or more of the population lives at or below the federal poverty level in 20 metropolitan Portland census tracts, including some amid outlying suburbs, according to U.S. Census Bureau data published Tuesday.