“AV-Test.org Reports Stats from Antivirus Roundup”, from PC Magazine
http://www.pcmag.com/article2/0,1895,2135092,00.asp
AV-Test.org, an independent testing group at the Otto-von-Guericke-University (Magdeburg, Germany), tested 29 anti-malware products with a very large set of files (606,901 to be specific). The goal was to test detection capabilities only, not cleaning. Products were set with their most aggressive detection options, such as using all heuristics and testing inside archives.
Avast! was 8th place.
Detected = 584,574
Detection = 96.32%