With 3,635 apartments added to Denver’s multifamily inventory during the fourth quarter last year, the vacancy rate increased to 6.4% from 5.4% during the third quarter, according to Pinnacle Real Estate Advisors' multifamily report.

“Construction of apartment buildings is leading the Denver metro area’s building boom,” according to the report. “New construction will help meet the rising demand as Denver continues to be an attractive city for people to move to.”

Colorado added 77,059 residents last year, bringing the state’s total population to just over 5.6 million, according to the U.S. Census Bureau. That number lags the nearly 90,000 residents added in 2016 and the 98,000 in 2015.

“Colorado’s attractive lifestyle and robust economy continue to draw people to the region, continuing the demand for quality rental housing in a market that remains tight even while new apartments are being built at a rapid pace,” the report states.

Though average rental rates fell during the quarter to $1,396 compared to the previous quarter, they were up from $1,347 during the same time last year and $1,292 in 2015. In 2002, the average rent was about $800.