CENTR have just published their quarterly statistical report.
Naturally the report is focussed more on European ccTLDs, but it contains plenty of data on domains at a global level.
You can grab the full report here
About Michele Neylon
Michele is founder and managing director of Irish domain registrar and hosting company Blacknight. Michele has been deeply involved in domain and internet policy discussions for more than a decade.
He also co-hosts the Technology.ie podcast.