XML Schema is not yet widespread??

Hi
I was wandering to how can I know the current extent of XML Schema on
the Web. Because I saw a paper by Mignet et al (2003), that say:
"conceptual schemas on the XML Web is not yet widespread: only 48% of
the documents reference DTDs while the number of documents that
reference XML Schema specifications is insignificant (0.09% of all
documents)."

So, is it still right, and how I can know the current extent of XML
Schema on the Web?

Thanks all.