This graph is a bit deceptive in that the first budget (2001) was actually in place when Bush was elected so generally his first budget year is Sep 2001 - Sep 2002. In addition, that makes Obama’s first budget actually Bush’s last budget although Obama did revise the Fiscal Year 2008 budget early in his Presidency and add a bunch of spending to it. To be totally accurate one would have to figure out which part of the 2008 budget belongs to each administration.