2017 22.0754578754579
2016 22.2579234972678
2015 22.7187755102041
2014 21.8435616438356
2013 22.012893982808
2012 22.0603825136612
2011 22.38
2010 22.5564383561644
2009 21.7419178082192
2008 21.4021857923497
2007 21.8296819787986
2006 21.9953038674033
2005 22.2692771084337
2004 22.0243902439024
2003 22.0903426791277
2002 21.7854103343465
2001 21.8886904761905