Over the last few weeks, why has Avast's zero day protection fallen so much?

[nine9s]

Avast used to consistently be in top 3 (over a year period it is still #1), with a zero-day prevention rate of about 80-95% every day on this site that does a running daily test of zero-day protection of pretty much all the antivirus programs:

http://www.shadowserver.org/wiki/pmwiki.php/AV/VirusDailyStats

But over the last few weeks it has fallen to the 30-50% range in protection and toward bottom of the long list of programs tested.

You can see weekly, monthly, 90, 180 days, 1 year results and see the slide.

Anyone know what was changed in Avast over the last few weeks?

[Aventador]

Lol..............And you honestly believe some bogus site such as what you link to? Why don't you check out a real legit site such as AV Comparatives, VB 100 and AV-Test.org. Come back to me after you check those real sites out.

[nine9s]

As I wrote, Avast had been top on that site for a while.  Those other tests are good, but the one I cited does a daily test, while the other are quarterly at best.  I use Avast - I am not knocking it.  I just want to know if something recently changed.

[Aventador]

http://westcoastlabs.com/realTimeTesting/article/?articleID=1

[nine9s]

That is 2011 data, per that page.