How unusual is President Obama’s vacation at Martha’s Vineyard?

President Obama arrived in Martha's Vineyard, Mass., Thursday for a family vacation that is sparking a small amount of controversy because of the president's choice to spend 10 days on the tony New England island amid a major economic crisis.

Last night, Sarah Palin labeled the president's decision "very, very tone deaf" during an appearance on Fox News. She suggested that voter displeasure over the trip will prompt Obama to return early to Washington, D.C.

Does Obama take too many vacations? Does he take more vacations than his predecessors? What does he actually do on vacation? Mark Knoller, the White House correspondent for CBS News, is offering some answers to those queries.

Knoller reports that this current trip marks Obama's 11th vacation--ranging from 2 days to 10 days--since taking office. And Knoller notes that even though the president says he's on vacation, it doesn't mean he gets time off from his presidential duties.

"I deliberately put quotation marks on the word 'vacation' as recognition that a modern U.S. president is never really on 'vacation,' not the way most people understand the word," Knoller writes.

He notes that other presidents have endured similar criticism for personal travel. Obama's vacation time has totaled all or part of 61 days by Knoller's count, while Ronald Reagan's 43 visits to his ranch amounted to a total of 349 vacation days. George W. Bush, criticized for time spent at his Texas ranch, made 77 visits to Crawford, Texas, which added up to 490 days on vacation.