| Year | Value | | 2023 | 5,831 | | 2022 | 5,849 | | 2021 | 5,815 | | 2020 | 5,754 | | 2019 | 5,653 | | 2018 | 5,529 | | 2017 | 5,431 | | 2016 | 5,360 | | 2015 | 5,318 | | 2014 | 5,338 | | 2013 | 5,431 | | 2012 | 5,537 | | 2011 | 5,544 | | 2010 | 5,442 | | 2009 | 5,342 | | 2008 | 5,265 | | 2007 | 5,227 | | 2006 | 5,217 | | 2005 | 5,211 | | 2004 | 5,249 | | 2003 | 5,333 | | 2002 | 5,429 | | 2001 | 5,500 | | 2000 | 5,543 | | 1999 | 5,562 | | 1998 | 5,553 | | 1997 | 5,513 | | 1996 | 5,417 | | 1995 | 5,284 | | 1994 | 5,175 | | 1993 | 5,129 | | 1992 | 5,152 | | 1991 | 5,243 | | 1990 | 5,401 | | 1989 | 5,604 | | 1988 | 5,830 | | 1987 | 6,045 | | 1986 | 6,143 | | 1985 | 6,094 | | 1984 | 5,972 | | 1983 | 5,821 | | 1982 | 5,684 | | 1981 | 5,586 | | 1980 | 5,523 | | 1979 | 5,484 | | 1978 | 5,451 | | 1977 | 5,406 | | 1976 | 5,259 | | 1975 | 5,026 |
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