The Netcraft Web Server Surveys have been around 20 odd years.
The April Survey reports http://news.netcraft.com/archives/20...er-survey.html "In the April 2014 survey we received responses from 958,919,789 sites — 39 million more than last month."
A significant proportion will be parked domains. But that said a billion web sites is a lot.
NGINX is the big gain! Crunching IIS in the Top 1 Million Sites.