It's interesting that UTF-8 has largely achieved its success amongst English speakers and Latin-1 languages--almost everything else has remained more or less static or has a slow downward trend.  Since we're not seeing an increase in UTF-16 or UCS-2 or anything else like that, this would seem evidence that the Web, or at least Google's view of it, is becoming even more increasingly dominated by Western European languages, which is itself an interesting idea.