Only 1 in 6 million couples reach 80 years of marriage. This pair just did.

A U.S. couple is sharing their advice on what makes for a long, happy life together after 80 years of marriage.

Minnesota — A St. Cloud couple both recently turned 99 years old. And they just marked another, even rarer milestone: 80 years of marriage.

Betty and Kermit Eastman celebrated their oak anniversary on June 6, joining a remarkably small group. On average, only one U.S. couple each year reaches the 80-year mark. Globally, it is estimated that only one in 6 million couples live long enough to celebrate eight decades together.

Their story began in Thief River Falls, where Betty moved into the neighborhood and caught Kermit’s attention.

“I remember one time her dad said to her, ‘I wonder what that Eastman boy is doing walking up and down the sidewalk,’” Kermit said.

Betty remembered what first stood out about him.

“He had a lawnmowing business when he was really young,” she said.

Before the couple could build much of a life together, Kermit left high school to join the Navy during the Second World War. His ship, the U.S.S. Mullany, was struck by a Japanese kamikaze pilot.

“We were hit by a suicide plane,” Kermit said. “We lost quite a few guys. About 20, I think.”

After returning from the war, the two married, and both went back to finish high school.

“My senior year, well, I was married,” Kermit said.

They also attended prom together as a married couple.

After college, they settled in St. Cloud, where Kermit worked as a superintendent. They raised two children and now have five grandchildren, 11 great-grandchildren and three great-great-grandchildren. The couple celebrated their anniversary at their daughter’s house with their entire family.

After eight decades, both said the formula is straightforward.

“Just don’t keep secrets and be honest,” Betty said.

“Tell it like it is,” Kermit said. “Just live every day. Every day is a gift.”

John Lauritsen, Cnn