Center for Responsive Politics

Congressmen, lobbyists, and car salesmen have some of the worst reputations for honesty and ethics, as do business execs, stock brokers and real estate agents. And there's a reason why: The rules of their games are stacked against good behavior.

Mitt Romney's net worth: $200 million. Barack Obama's response to Romney's claim that he's "out of touch" with the concerns of ordinary Americans: Priceless. "I bought my first car for about $900," said Obama. "It had a big hole in the floor that allowed you to see the road, so I knew my wife wasn't marrying me for my money."

Approximately 60% of first-year U.S. senators and 40% of House of Representatives freshmen are worth at least $1 million, according to the Center for Responsive Politics. That makes them far richer than most of the Americans they represent: Just 1% of the country's population has reached the $1 million mark.

Despite a market meltdown, the men and women of Congress posted a 16% gain collectively between 2008 to 2009, according to a study by the Center for Responsive Politics. Another finding: virtually half of Congressional members are millionaires, including eight mega-millionaires.

What companies have shelled out the most to America's political campaigns? Using data from the nonpartisan Center for Responsive Politics, we've created a top-10 list, offering a look at the candidates they support, the issues that concern them and their lobbying habits.