Sacramento isn't keeping up with the demand for apartment units even as more people flood into the area.

Apartment construction is at a 20-year high in the U.S., due to most of the nation's biggest cities seeing rapid growth in their rent stock, according to a new Rent Cafe report.

Sacramento is seeing the fastest rising rent in the nation and an influx of people, primarily from the Bay Area, moving to the region in search of more affordable metro living. However, despite the rapid growth and nationwide apartment boom, the Sacramento region is among the worst markets in the country for apartment construction.

There are only 738 new units in large-scale developments expected to be completed this year, according to data provided by Yardi Matrix, a sister division of Rent Cafe.

This makes it the second worst large metro for apartment construction in nation. New Orleans tops the list for the worst metro for apartment construction with only 501 units expected to be delivered this year.

So far this year, the Sacramento region has gained nearly 29,000 new residents, a 1.3 percent increase from last year. The number of new apartment units available is simply not sustainable for the movement happening in the area. This is one of the reasons why rent in Sacramento has been skyrocketing.

It recently hit $1,325, up 8.4 percent according to the report.

The Sacramento area is also seeing a high occupancy rate at 96.7 percent, making the need for apartment construction even greater.

While it's easy to blame younger people for rising rent, the report found that Baby Boomers are contributing to the trend as well. More Baby Boomers are choosing to rent to eliminate property upkeep and financial strings attached to homeownership. Renters are also usually able to live closer to prime locations than people who buy homes in residential neighborhoods.

“Lifestyle changes, a housing-stock shortage and high homes prices have led to more people than ever – of all ages – choosing to rent an apartment rather than buy a home." Doug Ressler of Yardi Matrix said in the report.

Meanwhile, rent is cooling down in metros such as San Francisco, due to more apartment units being built. Close to 6,200 new units entered the San Francisco metro area in 2016, with about 5,400 apartments expected to be delivered this year and another 9,500 under construction.

But, there is a silver lining for Sacramento.

Ryan DeVore, director of Community Development for the City of Sacramento, told ABC10 there are currently 3,500 apartment units and condos which only need to apply for a building permit for construction to be approved.

There are also 1,000 units currently under construction which may not have been accounted for in the report because they are due to be completed after 2017. Additionally, 500 units are already in review for a building permit.

It takes about six months to a year for a unit to be ready for move-in after a building permit is issued, according to DeVore.

The addition of potentially 5,000 new units over the next few years could help relieve some of the stress of high rent in Sacramento.