Oregon's population is growing, but it's not because people are having kids.

According to new data from Portland State University's Population Research Center, Oregon's population increased by 54,200 between 2017 and 2018—exceeding 50,000 for the fourth consecutive year. Migration from other places accounted for 88 percent of that growth.

That's because the state's natural population increase—the number of births minus the number of deaths—is as low as its been since 1930. It's also a decrease from last year, when Oregon's natural population growth hit a 58-year low.

The number of births to Oregon residents was also "14 percent lower in 2017-18 than its recent peak in 2007-08." In fact, in 20 of Oregon's 36 counties there was a natural population decrease, meaning more people died than were born.

"These included eastern, southwestern, and coastal counties," the report notes. "In many, but not all counties, net in-migration (more people moving in than out) offsets these decreases."

Overall, population growth statewide this year was lower than last year, when Oregon added 64,750 new residents. Since 2014, 85 percent of the state's growth has been due to people moving from elsewhere.

Many of those people continue to pick Portland as the place to set up home.

This year, more people are moving to Stumptown than any other Oregon city—adding 9,640 new residents, or growing by 1.5 percent, in 2017-18. However, Bend's population has seen the highest percent increase, growing just over three percent in the last year.