Year | Value | 2022 | 24.973394448861 | 2021 | 24.599091050369 | 2020 | 24.364065441183 | 2019 | 24.494741339185 | 2018 | 24.236357534231 | 2017 | 23.806089932682 | 2016 | 23.408436769912 | 2015 | 22.9654683052 | 2014 | 22.191389134594 | 2013 | 21.289763349543 | 2012 | 20.47408690006 | 2011 | 19.79587775939 | 2010 | 17.600453159408 | 2009 | 15.569364577072 | 2008 | 13.71925429901 | 2007 | 12.129804391501 | 2006 | 10.778250008929 | 2005 | 10.426029354462 | 2004 | 10.146549613515 | 2003 | 9.810028899343 | 2002 | 9.5195641232102 | 2001 | 9.325092399538 | 2000 | 9.2234752445986 | 1999 | 9.1258876595679 | 1998 | 8.9773686804967 | 1997 | 8.9812270627582 | 1996 | 8.7855665341699 | 1995 | 8.6953300262483 | 1994 | 8.6422970863844 | 1993 | 8.7124971758455 | 1992 | 8.8009343388864 | 1991 | 8.8143123298142 |
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