President Obama’s annual family vacation — an escape to tony Martha’s Vineyard — has once again served as an inviting target for critics. They ask how he can relax while the world burns, wring their hands about "optics" (aka "how it looks to the average American") and recycle decades-old complaints about presidents enjoying high-end resorts and historically patrician sports like golf.

Just how many vacations has Obama taken since January 2009? How does he compare to his two-term predecessor, George W. Bush?

The authoritative figures come from CBS News Correspondent Mark Knoller.

Knoller has meticulously chronicled presidential data since 1996 with an attention to detail that has made successive White Houses regard his figures as more reliable than their own. He keeps tabs on everything from the number of trips overseas to the number of foreign leaders who visit the White House to the number of formal press conferences. He also tracks how often presidents flee Washington for what he calls "vacations" — always in quotes — which he notes can never be clean breaks from the job, thanks to modern communications, which bring global crises to the presidential doorstep no matter where it happens to be.

Knoller graciously shared his latest data with Yahoo News.

(Yahoo News/AP Photo)

As of August 12, 2014, Obama has taken 20 "vacations" lasting 2 to 15 days. He has spent all or part of 129 days on “vacation.”

And the president has made 33 visits to the official Camp David presidential retreat in Maryland, totaling all or part of 84 days. (Knoller does not count Camp David trips as “vacation.”)

Obama’s morning round of golf on Tuesday brought his total since January 2009 to 186, with 22 of them on Martha’s Vineyard.

At this point in George W. Bush’s presidency, he had taken 58 trips to his Prairie Chapel ranch near Crawford, Texas, for all or part of 381 days. (Bush also frequently used the property to host world leaders).

Bush had also spent all or part of 26 days at his family’s oceanside compound in Kennebunkport, Maine, over the course of seven trips there.

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And the former Texas governor had been to Camp David 108 times for a total of all or part of 341 days.

Bush played 24 rounds of golf as president. He later explained his decision to stop in the fall of 2003 by saying he felt it was not appropriate to be seen golfing while American troops fought in Afghanistan and Iraq.

Like Obama's, Bush’s vacations became a frequent target of criticism. But Bush also drew liberal protesters against his policies — the most famous of them antiwar activist Cindy Sheehan, who pitched a camp down the road from the Crawford ranch.

And Bush drew liberal scorn in August 2002 when he began a round of golf in Kennebunkport with a somber denunciation of a bus bombing in Israel.

"I call upon all nations to do everything they can to stop these terrorist killers," he said. "Now watch this drive."