Digging through the Sunlight Foundation's terrific investigation into "revolving door" lobbyists -- former Congressional staffers who make the move to K Street -- we found a single chart that absolutely blew our mind. Here it is.

Image courtesy of the Sunlight Foundation.

Here's the key takeaway: 7 in 10 former Congressional staffers who have become lobbyists generate more revenue than sitting Members of Congress make. (Worth noting: How much revenue a lobbyist generates is not directly equivalent to his or her salary.) Almost as amazing is the fact that former Congressional staffers turned lobbyists bring in more revenue than even former Members who themselves have become lobbyists. The student has become the master.

Given those numbers, is it any wonder that working in Congress -- whether as a staffer or a Member -- is viewed by an increasing number of people as a way station on the way to a more lucrative career in lobbying? There are, without doubt, elected officials and staff who view public service as an end in itself, no matter the financial repercussions of that decision. But, the massive disparity between what you can make in the public sector and what you can collect in the private sector is a siren's call that is hard to resist for many people. And as the revenue generated/salary paid gap continues to widen, it will become increasingly difficult to keep that revolving door between Congress and K Street shut.