| Year | Mean CH4 (ppmv) | Mean O3 (ppmv) |
| 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 | 1740.994 1738.120 1737.331 1730.918 1740.740 1743.628 1750.178 1746.312 1759.923 1773.787 | 56.262 57.253 54.501 57.139 55.272 58.556 57.259 58.033 58.319 56.800 |