Whichever way you slice it, the U.S. economy has now been creating jobs for 22 consecutive months.

But you wouldn't know it from the rhetoric Republican presidential candidates have been spouting on the trail.

"This president has been on the attack and has been a job killer," GOP frontrunner Mitt Romney told a town hall meeting in Salem, N.H., on Thursday, repeating a slam he uses regularly against Obama.

"It's very clear that under Obama's job-killing policies, we're not going to get out of this deep unemployment," Newt Gingrich told Fox in July.

"Either the president's economic policies are killing this economy, or his lack of leadership," Rick Santorum said in September. "Either way, President Obama is to blame."

The "job killer" theme has been a hallmark of the Republican campaign for the White House, and one that party strategists say will be most effective in pummeling Obama in the months ahead.

But it could be quickly losing its punch.

The U.S. economy added 200,000 private sector jobs in December, the Labor Department reported today, better than the 150,000 economists expected. Meanwhile, the unemployment rate ticked down to 8.5 percent - the lowest level since March 2009.

All told, the economy added 1.6 million jobs in 2011 after adding 940,000 in 2010, the Department said.

"More private-sector jobs were created in 2011 than any year since 2005," Obama said today, taking credit for the gains. "After losing more than 8 million jobs in the recession, obviously we have a lot more work to do.  But it is important for the American people to recognize that we've now added 3.2 million new private sector jobs over the last 22 months."

Romney called the lower unemployment rate "good news" in a paper statement two hours after the report was released - no mention of "job killer" - but he insisted Obama's policies have "slowed the recovery and created misery for 24 million Americans who are unemployed, or stuck in part-time jobs when what they really want is full-time work."

The latest jobs report did show little change in the number of long-term unemployed and the rate at which people are entering the work force.

Still, nearly two years of steady job gains stands to refute the claim that Obama has been "killing" jobs overall.

When asked whether the trend undermines Romney's "job killer" attack, spokeswoman Andrea Saul pointed to the 1.7 million net job loss since 2009, calling it "atrocious."

"President Obama is on track for the worst jobs record of any president in modern history. Period," she said in an email.

She did not note that most of the jobs lost under Obama disappeared in the first 12 months of his term, continuing a trend of deepening unemployment that began under President George W. Bush when the recession began.

"It's hard to overstate how important the unemployment rate is to Barack Obama's re-election prospects, not just the number, but its trajectory, and the closely related public perception of the condition of the economy overall," said ABC News pollster Gary Langer.

"Note that as unemployment has eased, consumer confidence has improved to its best in nearly six months, and the president's job approval advanced to 49 percent in recent ABC/Post and CNN polls - his best in 9 months, excepting a brief bin Laden bounce," he added.

Analysts say the economy now must add roughly 200,000 to 250,000 jobs every month to effectively lower the unemployment rate to below 8 percent. The unemployment rate was 8.3 percent in February 2009, Obama's first full month in office.

ABC News' Tom Nagorski and Zunaira Zaki contributed to this report.