The 2013 AAF factors have been released by HUD.  HUD establishes the rent adjustment factors — called Annual Adjustment Factors (AAFs) — on the basis of Consumer Price Index (CPI) data relating to changes in residential rent and utility costs.

The Annual Adjustment Factors (AAF) are effective May 22, 2013.

You can find the AAFs on HUD Data Sets located here:  http://www.huduser.org/portal/datasets/aaf.html 

The AAF tables can also be found here: 2013 AAF Factors