Offshore drilling rigs
Total number of offshore drilling rigs dropped from 377 to 304 (20%) in the last 12 months to August 2015. Over the whole period from 2000, the GOM share dropped to 20%. Asia Pacific’s share increased, mainly offshore India and China.
Source of graphs: http://www.eia.gov/todayinenergy/detail.cfm?id=23032#tabs-4
Note the months in which the number of drilling rigs started to increase substantially. In 2005 we had the beginning of the global crude oil peak, in 2010/2011 the US shale oil boom took off.
Data are from Bake Hughes http://phx.corporate-ir.net/phoenix.zhtml?c=79687&p=irol-rigcountsintl