SEATTLE — Seattle’s record construction boom may have peaked: Development activity across the central part of the city is declining at the fastest rate in at least 12 years.

At the end of this past year, there were 57 active projects underway in the area that stretches from South Lake Union to Sodo, according to a report by the Downtown Seattle Association. That’s down from a record high of 74 projects six months prior.

The 23 percent decline amounts to the biggest six-month drop since the downtown association began its twice-a-year construction counts in 2005.

It occurs after a recent survey found Seattle’s crane count had dipped for the first time in years.

Of course, the slowdown is all relative: Even with the recent decrease, the development activity going surpasses anything seen before 2015 — even beating out the surge from this past decade before the recession hit. And Seattle’s falling crane count is good enough to lead the country.

On one hand, nearly half of the projects underway are set to wrap up by the end of the year, and the downtown group expects fewer apartments to open in the next few years than in 2017.

But there are 220 potential projects in the pipeline for the greater downtown region (not all of those will get built, and some will be delayed many years, but several are in the final planning stages).

The construction frenzy that began half a decade ago has remade the skyline and added density to areas once filled with parking lots, as apartments and offices sprout up to transform the city.

As residents and commuters know all too well, the surge has caused headaches: It’s tough to travel even a few blocks without hitting a closed street, a blocked sidewalk or closed-off street parking, and jackhammering noise has become an unofficial soundtrack to city life.

About two-thirds of the projects getting built have a residential component, and almost all of those are apartment buildings.

About 5,700 apartments opened in the past year across the greater downtown region, and an additional 3,600 are set to be completed this year.

Rents downtown have begun dropping for the first time since last decade amid the construction boom, as some of the new luxury apartments opening in the city’s hottest neighborhoods have sat empty. Altogether, the area has added more than 20,000 new housing units in the past decade.

There are up to 30,000 apartments left in the pipeline, though developers recently have reported a pullback in new apartment plans now that rents are no longer keeping up with rising construction costs.

The second-most common type of development — new office buildings — is on the decline.

After peaking with 5 million square feet of office underway at the end of 2015 and 2016, office construction fell to 3.6 million square feet at the end of 2017. The downtown association has about 10 million square feet identified in the pipeline for the next three years.

Amazon continues to drive the office market — and through its employees, the apartment market — as it looks to add several million square feet through the next few years. It recently has begun expanding beyond South Lake Union and the Denny Triangle and into the downtown core. But huge projects for Google and Facebook are also underway, and some developers are building offices without tenants lined up.

Hotel-room openings, which fell off a cliff during the recession, are set to boom this year because of the planned opening of the 1,260-room Hyatt Regency at Eighth and Howell. It will be the biggest hotel in the Pacific Northwest when it opens this fall.