WASHINGTON (AP) - The tax package negotiated by President Barack Obama and Senate Republicans and passed by Congress will protect 99 percent of Americans from an income tax increase. But that doesn't mean that most of them won't see their taxes rise.

In fact, the vast majority of workers will pay higher federal taxes in 2013, largely because a temporary reduction in Social Security payroll taxes expired on New Year's Day. The tax package did nothing to prevent that from happening.

A nonpartisan Washington research group, The Tax Policy Center, estimates that 77 percent of American households will face higher federal taxes in 2013 under the agreement. High-income families would get the biggest tax increases, but many middle- and low-income families will pay higher taxes too.