(Thomson Reuters) U.S. President Obama is applauded by Vice President Biden during State of the Union address to a joint session of Congress on Capitol Hill in Washington

Americans are feeling much more optimistic about the country's economy.

That is, Americans who aren't Republicans.

In a survey of the prevailing economic attitudes over 40 countries, the Pew Research Center found that 40 percent of US citizens thought the economy was "good" while 56 percent said it was not.

That is up 23 points from the low in 2009.

The rise in confidence isn't too surprising, given recent reports on consumer sentiment moving back up to pre-2007 levels, the budget deficit falling and unemployment rate decreasing.

What is striking, however, is that the level of confidence varies dramatically depending on political allegiances.

While 55 percent of Democrats reported feeling positive about the economy, for example, just 25 percent of Republicans felt the same from March 25 to May 27.

When asked if they thought the economy would improve over the next 12 months, 53 percent of Democrats said yes. Only 23 percent of the Republicans in the survey agreed.

The same perception gap extends to the far future, with 41 percent of Democrats believing that the next generation will be better off than their parents, and just 24 percent of Republicans saying the same.

Nothing new

This partisan divide on economic attitudes is nothing new.

In a seperate set of studies by the Pew center, researchers asked Democrats, Republicans and Independents to rate the condition of the economy as excellent, good, fair or poor.

(Pew Research Center)

That study shows that confidence in the economy started to fall at the start of the financial crisis through early 2008 — though the partisan division still held strong.

In January of that year, 46 percent of Republicans said they felt good about the national economy versus 15 percent of Democrats.

By October that year, just 11% of Republicans felt good about the economy, while 10% of Democrats felt the same way.

Fast forward to May 2015, and Republicans are still generally down on the economy, with 17% describing it as good or excellent. In contrast, 39% said economic conditions were poor.

More than a third, or 36%, of Democrats were positive on the economy, with 23% describing it as poor.

The resulting graph looks something like a horizontal double-helix. Confidence levels shift as presidents from alternating parties take power, according to Andrew Polsky, professor of political sciences at the City University of New York, Hunter College.