We've updated our Stimulus Progress Bar, which tracks the movement of stimulus dollars through federal agencies. Our numbers show a significant gap between agencies in the speed with which they obligate their stimulus money.

Last week, we explained why, in the view of many federal agencies, the number to watch when it comes to measuring progress isn't how much money has been paid out, but rather how much money has been obligated (or committed, or awarded) to a specific project. That, of course, is the number over which agencies have the most control.

Using that measurement, nearly 60 percent of the $580 billion in federal stimulus spending (as opposed to tax cuts) has already been obligated. By comparison, a little less than 20 percent has been paid out.

The variation among agencies is extreme. According to Recovery.gov, many agencies have obligated the vast majority of their stimulus funding, including the Department of Labor (77 percent), the Department of Justice (99 percent), the National Science Foundation (80 percent), and the Environmental Protection Agency (99 percent). Not all of that money is stimulating the economy yet, but to use a military metaphor, it's mobilized and awaiting deployment.

At the other end of the spectrum are a handful of agencies that have obligated less than a quarter of their stimulus dollars -- eight months after the Recovery Act passed. One is the Department of State, to which Congress appropriated $602 million in stimulus money. The department's Web site states just how that money was intended to be spent. But as of Monday, just $144 million had been obligated, and only $25 million paid out.

(We called the department for an explanation and will post its response once we get it.)

Other agencies that are obligating their stimulus money slowly include the Department of the Interior (30 percent obligated), the General Services Administration (31 percent) and the Department of Agriculture (26 percent). To see the progress of each agency, visit our Stimulus Progress Bar.