Each year, the president submits a budget that details the upcoming year's spending and revenue expectations, but also forecasts spending and revenues for several years into the future.
How well do those forecasts match reality? Not very, as the chart below shows.
Select the budget forecasts using the buttons below and you'll quickly see how far off a projected budget can be from reality.
In 2008, for example, the budget forecasted a 2009 deficit of $187 billion. In reality, the deficit that year ended up being $1.419 trillion. That's nearly 10 times the projection.
Hover over the pins at the bottom of the chart to see major political/economic news that influenced the budget.
Note: The federal government's fiscal year runs from Oct. 1 to the following September 30.