[Zope] What's up with netcraft?

I noticed that the latest netcraft survey shows that there are 4056 live Zope servers on the net in August. http://www.netcraft.com/Survey/Reports/0108/ This is down from 11756 servers in July. Here is a graph: http://www.ozzope.org/aboutzope/ What is going on here? Did half the people running Zope suddenly switch off their servers or did Netcraft muck up their stats last month? Cheers, David.