About 13.7 million visitors to South Dakota spent nearly $3.8 billion in in 2015, officials said Thursday in calling it a strong year for one of South Dakota’s most important industries.

Low gas prices and landmark anniversaries such as the 75th Sturgis Motorcycle Rally and the 50th Custer State Park Buffalo Roundup helped draw tourists, Secretary of Tourism Jim Hagen said. But he said visitor levels apart from those events stayed strong into the fall for a “tremendous year.”

“You can feel it in the air,” Hagen said. “It’s palpable when you’re having a good summer.”

Gov. Dennis Daugaard said the number of visitors increased by nearly 3 percent over 2014. Roughly 13.3 million tourists spent just over $3.7 billion in 2014, according to a report prepared for the department.

Tourism’s contribution to South Dakota’s economy climbed 6.1 percent in 2015, generating more than $270 million in state and local tax revenue and supporting more than 50,000 jobs, according to the state Department of Tourism.

Daniel Becker from Ohio spent several days in South Dakota as part of a roughly 2,300-mile road trip to explore a handful of states he’d never seen before. The 44-year-old custom cabinet designer said he watched the sun rise in the Badlands, took in Mount Rushmore National Memorial and saw his first buffalo — when a half-dozen of them caused a traffic jam in Custer State Park in the western part of the state.

“It was just breathtaking,” Becker said of the park scenery.

Visitors to the park were up 11 percent compared to the year before and revenue was up about 14 percent, an official said. Craig Pugsley, park visitor services coordinator, said the buffalo roundup drew record attendance and around rally time the park brought in over $200,000 more from motorcycles than during the same period last year.

“The weather throughout September and October was gorgeous,” Pugsley said.

Daugaard said 2016 is expected to be another strong year for tourism as gas prices are projected to remain low. State officials are looking forward to the centennial of the National Park Service and the 75th anniversary of the completion of Mount Rushmore.

Robust 2015 numbers also mean the state has more money available to spend on advertising South Dakota for the following year, Daugaard said.

“Good tourism begets even better tourism,” Daugaard said.

Photo Credit: Mount Rushmore National Memorial in the Black Hills of South Dakota. Mike Stewart / Associated Press