The final lobbying expenditures reports for 2013 have been filed, so it's time to look at some of the highlights for Washington, D.C.'s multibillion-dollar influence industry:

U.S. Chamber spends less, but it's still No. 1

The U.S. Chamber of Commerce continues to spend more on lobbying than any other organization in Washington, D.C., but its spending fell to $52 million in 2013, thanks to gridlock on Capitol Hill.

That's way below 2012's lobbying total of $136 million, according to the Center for Responsive Politics. The chamber, however, counts "voter education" as a lobbying expense, so its lobbying expenditures spike during election years.

What's most noteworthy about 2013's number is that it's the chamber's lowest lobbying level for a non-election year since 2005. Why spend a lot of money when Congress isn't enacting much legislation?

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