Year | Value | 2022 | 28.074531271252 | 2021 | 27.870566864265 | 2020 | 27.470132720055 | 2019 | 27.62252364112 | 2018 | 27.794267133676 | 2017 | 28.427175737278 | 2016 | 29.143736986266 | 2015 | 27.101517902908 | 2014 | 27.039226877499 | 2013 | 26.92280569411 | 2012 | 26.639625143383 | 2011 | 26.274281055609 | 2010 | 25.924316012341 | 2009 | 25.634798552642 | 2008 | 25.330773411031 | 2007 | 25.070332934873 | 2006 | 24.773724294756 | 2005 | 24.866471595491 | 2004 | 24.281029678582 | 2003 | 24.308138901282 | 2002 | 24.291575711075 | 2001 | 23.820584709204 | 2000 | 23.592711410293 | 1999 | 23.390465682741 | 1998 | 23.185507661741 | 1997 | 23.221139299498 | 1996 | 22.803125413784 | 1995 | 22.684442039676 | 1994 | 22.700315579836 | 1993 | 22.708101344841 | 1992 | 22.745942875981 | 1991 | 22.794511358657 |
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