"American women say they feel pressure to renounce even from their husbands."

Last year, almost 1,800 people followed Superman's lead, renouncing their U.S. citizenship or handing in their Green Cards. That's a record number since the Internal Revenue Service began publishing a list of those who renounced in 1998. It's also almost eight times more than the number of citizens who renounced in 2008, and more than the total for 2007, 2008 and 2009 combined.

But not everyone's motivations are as lofty as Superman's. Many say they parted ways with America for tax reasons.

The United States is one of the only countries to tax its citizens on income earned while they're living abroad. And just as Americans stateside must file tax returns each April - this year, the deadline is Tuesday - an estimated 6.3 million U.S. citizens living abroad brace for what they describe as an even tougher process of reporting their income and foreign accounts to the IRS. For them, the deadline is June.

Read More | "Special Report: Tax time pushes some Americans to take a hike" | Atossa Araxia Abrahamian | ?Reuters