| Year | Value | | 2021 | 4,031 | | 2020 | 4,029 | | 2019 | 4,030 | | 2018 | 4,030 | | 2017 | 4,030 | | 2016 | 4,029 | | 2015 | 4,019 | | 2014 | 4,023 | | 2013 | 4,032 | | 2012 | 4,070 | | 2011 | 4,072 | | 2010 | 4,097 | | 2009 | 4,150 | | 2008 | 4,144 | | 2007 | 4,143 | | 2006 | 4,146 | | 2005 | 4,154 | | 2004 | 4,259 | | 2003 | 4,318 | | 2002 | 4,318 | | 2001 | 4,320 | | 2000 | 4,320 | | 1999 | 4,290 | | 1998 | 4,290 | | 1997 | 4,292 | | 1996 | 4,293 | | 1995 | 4,294 |
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