OU Usage Statistics and Tier Shifts
This page shows OU's usage stats and tier shifts over Gen V, for those interested in the tier's history, and the most recent Gen VI movements. Note that from April 2011 to February 2012 and April 2012 to September 2012, OU's usage stats were not posted separately from the main batch of stats, so the usage stats for those months are organized among the rest of Smogon's tiers.
Recent Usage Statistics
Old Usage Statistics