| Year | Value | | 2023 | 29.815959530265 | | 2022 | 42.051987755714 | | 2021 | 32.531520055105 | | 2020 | 23.568981827852 | | 2019 | 28.573547970409 | | 2018 | 32.149575529711 | | 2017 | 29.025708343295 | | 2016 | 22.600148416985 | | 2015 | 28.121905009526 | | 2014 | 40.746653042627 | | 2013 | 42.759544424563 | | 2012 | 44.270339195606 | | 2011 | 46.793766637798 | | 2010 | 44.730315649594 | | 2009 | 40.367635523324 | | 2008 | 49.943121914334 | | 2007 | 45.364636693105 | | 2006 | 45.084483929383 | | 2005 | 39.704226829235 | | 2004 | 27.542557594335 | | 2003 | 26.031472350997 | | 2002 | 22.711728536874 | | 2001 | 23.663106483727 | | 2000 | 20.031455302368 | | 1999 | 14.47291912397 | | 1998 | 6.6188409812242 | | 1997 | 13.820883849698 | | 1996 | 2.1042839413745 | | 1995 | 7.2810737925766 |
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