Americans have despaired over the state of the nation’s economy for eight long years, but now, even before Donald Trump officially becomes president, their outlooks are turning rosier.

Last week, the New York-based Conference Board, which monitors issues affecting businesses, reported that consumer confidence in December soared to its highest level since August 2001. That followed a steep rise in November, after Trump won the election.

The measure is considered a key economic indicator and may provide clues to the economy’s direction. So it’s good news.

And there’s more of that, it seems, to come:

Americans, the group found, are more upbeat about their outlook than at any time in the last 13 years.

More consumers, 24 percent, foresee brighter “business conditions” in the next six months, the highest level since 2011.

A greater share also believes job availability — and their incomes — will grow.

Some 44 percent had a positive outlook for stock prices rising — the most upbeat appraisal since 2004.

And more Americans say they plan to buy cars and major appliances.

The findings are in line with survey results from the University of Michigan and the National Federation of Independent Business.

A new Associated Press-Times Square Alliance poll also reflects swelling optimism. While only 18 percent thought things got better for the nation in 2016, compared to 33 percent who thought they got worse, a whopping 55 percent think conditions will improve for them personally in 2017. That’s a 12-point jump from last year.

“Next year will be better than this year, because people will have more jobs and they’ll have more money to spend,” Bourema Tamboura, a Harlem resident, told the AP.

It’s hard not to see a link to Trump’s vows to grow the economy and create jobs through tax cuts, streamlining regulations and energizing the energy market.

True, no one — not even the leader of the Free World — can guarantee any particular level of growth. As the Conference Board’s Lynn Franco notes, “consumers’ continued optimism will depend on whether or not their expectations are realized.”

But here’s the thing: The economy’s fate rests in part on perceptions; a positive or negative outlook can become a self-fulfilling prophecy, as people spend and invest based on their personal expectations.

So if folks believe Trump will “make America great again” — bringing back jobs and raising income levels — that in itself is a big step toward making it happen.