Two booming Texas cities are seeing some of the smallest apartment rent gains in the country.

Austin apartment rents were unchanged from a year ago and Dallas rents rose by less than 1 percent in a new nationwide rental market update from Richardson-based RealPage.

"Some of the country's biggest markets register largely flat rents, with prices up less than 1 percent from a year ago," RealPage analysts said in the just-released report. "Seattle and Dallas are among the metros where rent growth has slowed most dramatically during 2018."

During recent years Dallas-area apartment rents have seen some of the biggest increases on record, with annual rent hikes of close to 6 percent.

But with thousands of new apartment units opening their doors, landlords have had a tough time getting more money out of their residents.

More than 30,000 apartments are still under construction in North Texas and will be delivered in the next couple of years. D-FW has more apartment building than any U.S. metro.

Nationwide apartment construction is also near an all-time high.

"We're at best only halfway through the period of peak deliveries," RealPage chief economist Greg Willett said in the report. "Ongoing construction of market-rate product totals just a hair under 400,000 market-rate units in the RealPage count, with annual deliveries set to stay right around 300,000 units through the middle of 2019."

While Dallas-area rent increases are stalling, apartment rents in Orlando have risen almost 7 percent this year and Las Vegas rents are up about 6 percent from a year ago.

Fort Worth-area rents are about 3 percent higher than in second quarter 2017, according to RealPage.

While Dallas-area apartment rent increases are slowing, average rents are still at an all-time high of more than $1,000 a month. And new apartments in North Texas urban areas can cost $1,500 and more.