11:22 p.m. EST February 27, 2014   WASHINGTON — Members of Congress took more than $3.7 million worth of free trips last year — the highest price tag for privately funded travel in a decade, new data show.

Family members — mostly spouses — went along for the ride on more than 40% of the trips, according to a USA TODAY analysis of Political MoneyLine data.

After ethics rules changed in 2007, the travel has mostly been paid for by charitable or educational groups instead of corporate interests or lobbyists. The rules now cap foreign trips at seven days.

Many of the non-profit groups paying the bills, however, have a distinct public-policy agenda. The biggest sponsor remains a foundation affiliated with the influential pro-Israel lobbying group American Israel Public Affairs Committee or AIPAC. The group holds its annual policy conference in Washington, D.C., next week.

AIPAC's foundation funded 77 trips, totaling nearly $1.4 million in value, records show. By contrast, a more moderate pro-Israel group, the J Street Education Fund, sponsored four trips.

Altogether, the spending helped make Israel the most popular travel destination for Congress in 2013.

"These groups wouldn't do this unless there was a goal they were trying to accomplish," said Kent Cooper of Political MoneyLine, which tracks congressional travel and campaign contributions. "They are spending this money to show (lawmakers) a point of view."

In all, Political MoneyLine data show 493 trips in 2013, up from 402 during 2012, an election year. Lawmakers typically cut down on privately funded travel during the campaign season.

AIPAC spokesman Marshall Wittman said the trips run by AIPAC's charitable arm are among "the most substantive, educational, rigorous and valuable" foreign-policy travel for Congress. He said lawmakers"hear from speakers representing diverse views across the political spectrum," including Palestinian officials

The second most popular destination was closer to lawmakers' workplace and far less expensive: Sixty-eight lawmakers reported attending a retreat in Baltimore for conservative lawmakers sponsored by the conservative Heritage Foundation think tank. Total price tag: $70,162.

Heritage's political arm has become more aggressive in recent years, opposing a recent vote in Congress that suspended the nation's debt ceiling without conditions and encouraging the conservative revolt against President Obama's health care law that led to last year's partial shutdown of the federal government.

The Heritage retreats are not about lobbying, said spokesman Michael Gonzalez. He said they are "educational opportunities" to share "policy solutions" with conservatives on Capitol Hill.

Liberals in Congress had their own getaway, too. Nearly two dozen Democrats traveled to a Baltimore suburb in January 2013 for a "strategy summit" sponsored by Progressive Congress, the non-profit group aligned with liberal activist groups.

Rep. John Garamendi, D-Calif., had the most expensive itinerary of any lawmaker, taking nearly $70,000 worth of trips in 2013. His wife, Patricia, accompanied him on a $40,000 trip in February 2013 to South Sudan and Tanzania, organized by the aid group CARE and underwritten by the Bill and Melinda Gates Foundation.

David Ray, CARE's head of policy and advocacy, said it's important for policymakers "to see the work firsthand."

Garamendi, who sits on the House Armed Services Committee, said the trip helped him gain a better sense of foreign assistance work in both countries, along with the opportunity to hold meetings with key South Sudanese and U.S. officials about military issues in the fledgling nation. Fighting broke out there last December along ethnic lines.

Both Garamendi and his wife have a long history in the region. More than four decades ago, the newlyweds lived in neighboring Ethiopia as Peace Corps volunteers. Patricia Garamendi is a former associate director of the Peace Corps.

Why take a trip funded by a private group? Garamendi said it spares taxpayers the cost of expensive travel and gives him more flexibility than official congressional trips, which he described as "highly structured."

"I don't like to be a mushroom, kept in the dark and fed fertilizer," he said.