While luxury towers continue to command high rents in downtown Boston and Cambridge, suburban apartment markets are leading the region in rent growth.

The south and southeast submarket spanning parts of Plymouth and Bristol counties had the region’s largest rent gains in December, increasing 10.2 percent year-over-year to $1,680, according to Dallas-based researchers Axiometrics. It was followed by the South Shore/Route 128 submarket, which increased 7.1 percent to $1,935, and the North Shore/Merrimack Valley area, up 6.5 percent to $1,798.

The average apartment in Boston rented for $2,187 a month in December, up $92 from December 2014.

“Boston apartments are performing at a higher level now than at any point in the past 4.5 years, and job growth is above the national level, so this market will remain strong,” Stephanie McCleskey, Axiometrics vice president of research, said in a statement.

Across the Greater Boston region, rents rose 4.4 percent in December, the slowest rate of increase since September.

Boston traditionally has one of the nation’s highest apartment occupancy rates, and that shows no sign of changing, with 94.5 percent of apartments rented in December, down just 0.1 percent from December 2014.

The report is based upon an Axiometric survey of rental properties, primarily buildings with 50 or more units.