| 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | |
| Onshore | 13.1 | 7.5 | 6.0 | 7.9 | 17.3 | 10.9 | 18.5 | 47.0 | 7.1 |
| Offshore | 0.3 | 1.8 | 0.5 | 0.6 | 0.4 | 4.0 | 3.0 | 1.6 | 0.7 |
| Total | 5.9 | 4.5 | 3.7 | 4.3 | 7.6 | 6.9 | 8.7 | 18.8 | 4.5 |
| Source: Annual reports (2003-2011) of the International Association of Oil and Gas Producers. Environmental Performance in the E&P Industry. London, United Kingdom. | |||||||||