This chart is from the WSJ:
Notice a few things.
1.) Defaults now are higher than they were in 2002-2003 at the beginning of this expansion.
3.) '02-'03 were the first two full years of this expansion.
That means sub-prime mortgage delinquencies are higher now -- 6 years into the expansion -- than they were at the beginning of the expansion.
A simple explanation may be delinquency rates were coming down in 20-03. This is possible. However, the fact we are six years into an expansion and delinquency rates are this high may indicate other problems -- such as the effect of lending money to everybody who has a pulse.