First, here is the ABX series 2007-2, tracking mortgage bonds issued mostly in the first half of 2007. It hit an all-time low of 64.83 Friday. The index was started in July 2007 at 100.
The 2007-1 AAA series also hit an all-time low on Friday. The AAA series are the most important to track simply because most subprime bonds were rated AAA when they were issued.