(CNN) — The National Park Service recorded a record-breaking 331 million visits during the National Park Service's centennial year in 2016, a 7.7% increase over 2015, the park service announced Friday, March 10.

"Our National Parks are our national treasures, and it's important to recognize that they are more than just beautiful landscapes," said US Department of the Interior Secretary Ryan Zinke, who made the announcement during a stop at Glacier National Park.

"Growing up near Glacier National Park, I understand the value these places bring to local economies and in preserving our heritage," Zinke said. "As we enter into a second century of service and visitation numbers continue to increase, we will focus on maintenance backlogs and ensuring these special places are preserved for future generations."

It was the park service's third consecutive all-time attendance record, and 77 national park sites set new records for annual recreation visits. (There are 417 sites in the National Park Service, and 382 of those sites count visits.)

Centennial year celebrations

Lots of attention went into celebrating the National Park Service's 100th anniversary year, with park service and non-profit campaigns across the country encouraging everyone to "Find Your Park."

Then-President Barack Obama created a total of 34 park sites during his eight years in office, including four in his final days in office this year. Some of those sites honored the country's civil rights struggle, African-American history, Japanese-American history and the fight for women's rights

Every fourth-grader around the country could get a free one-year national parks pass for the student and his or her family under the "Every Kid in a Park" program, which attracted more than 2 million students in its first year.

Four parks attract more than 40 million visits

Golden Gate National Recreation Area was the most popular national park site, attracting more than 15.6 million visitors last year, followed by Blue Ridge Parkway (15.2 million), Great Smoky Mountains National Park (11.3 million) and George Washington Memorial Parkway (10.3 million).

Eleven park sites attracted more than 5 million recreation visits each, including Grand Canyon National Park, Natchez Trace Parkway, Vietnam Veterans Memorial and Yosemite National Park.

Eighty parks had more than 1 million recreational visits.

Smaller parks also saw increases

Some 26 parks attracted half of the visits but smaller parks also saw larger increases in 2016 (13%) compared to 2015 (9%).

Four new parks -- Belmont Paul Women's Equality National Monument, Keweenaw National Historical Park, Manhattan Project National Historical Park and Paterson Great Falls National Historical Park -- were added to the count for the first time. They reported 300,000 visitors in their first year of existence.

And once people got there, they stayed longer than ever: Visitors spent some 1.4 billion hours in parks, an increase of 93 million hours from 2015.

More people stayed overnight: Overnight stays in parks were up 2.5% over 2015. That includes all overnight stays on park property, including concession-run lodges and campgrounds; park service-run campgrounds, backcountry camping and more.

Of those people staying overnight, there was a 12.5% increase in RV camping, a 4.8% increase in tent camping and a 6.7% increase in backcountry overnight camping compared with 2015.

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Most popular National Park Service sites (417 total)

Golden Gate National Recreation Area -- 15,638,777

Blue Ridge Parkway -- 15,175,578

Great Smoky Mountains National Park -- 11,312,786

George Washington Memorial Parkway -- 10,323,339

Gateway National Recreation Area -- 8,651,770

Lincoln Memorial -- 7,915,934

Lake Mead National Recreation Area -- 7,175,891

Grand Canyon National Park -- 5,969,811

Natchez Trace Parkway -- 5,891,315

Vietnam Veterans Memorial -- 5,299,713

Most popular National Parks (59 total)

Great Smoky Mountains National Park -- 11,312,786

Grand Canyon National Park -- 5,969,811

Yosemite National Park -- 5,028,868

Rocky Mountain National Park -- 4,517,585

Zion National Park -- 4,295,127

Yellowstone National Park -- 4,257,177

Olympic National Park -- 3,390,221

Acadia National Park -- 3,303,393

Grand Teton National Park -- 3,270,076