The U.S. Department of Health and Human Services has signed a $20 million contract to lease 55,627 square feet at the Columbia Center in downtown Seattle.

That brings the vacancy rate in the city’s tallest skyscraper down to about 24 percent, according to officespace.com.

Starting in April, the federal agency’s Seattle regional office will occupy the 16th and 17th floors and part of the 15th floor under a 10-year lease, with an option to extend the term by five years.

The agency now occupies 106,909 square feet at the Blanchard Plaza at 2201 6th Ave. in Seattle and says the move will save taxpayers nearly $10 million.