| Year | Value | | 2021 | 23,060.068131806 | | 2020 | 22,442.284665552 | | 2019 | 24,219.103258822 | | 2018 | 23,763.632678554 | | 2017 | 23,966.157122532 | | 2016 | 23,378.565034154 | | 2015 | 25,264.398318713 | | 2014 | 31,088.498767238 | | 2013 | 32,969.19454103 | | 2012 | 32,986.942712389 | | 2011 | 30,854.483196226 | | 2010 | 24,672.50968654 | | 2009 | 20,726.989505961 | | 2008 | 25,813.669684633 | | 2007 | 21,657.464773454 | | 2006 | 19,666.293228112 | | 2005 | 17,312.760458028 | | 2004 | 15,181.593522144 | | 2003 | 13,066.521235454 | | 2002 | 12,199.432818198 | | 2001 | 11,709.594729948 | | 2000 | 11,952.892074882 | | 1999 | 10,418.716740062 | | 1998 | 9,834.469539587 | | 1997 | 11,941.891178001 | | 1996 | 12,023.722177381 | | 1995 | 11,706.001974686 | | 1994 | 10,370.152082493 | | 1993 | 10,536.441789661 | | 1992 | 11,069.69687443 | | 1991 | 10,328.675299263 | | 1990 | 8,828.0522812372 | | 1989 | 8,187.0006006827 |
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