| Year | Value | | 2022 | 53.843368226372 | | 2021 | 53.578194170671 | | 2020 | 53.391456970221 | | 2019 | 53.63625184486 | | 2018 | 53.012373489402 | | 2017 | 52.284564191487 | | 2016 | 51.787704952458 | | 2015 | 51.360870496566 | | 2014 | 50.940182091586 | | 2013 | 50.48049854402 | | 2012 | 50.037957936758 | | 2011 | 49.599741317533 | | 2010 | 49.319671409512 | | 2009 | 48.983922548117 | | 2008 | 48.530436257547 | | 2007 | 48.011490633181 | | 2006 | 47.64234616032 | | 2005 | 47.257170346579 | | 2004 | 46.759343168884 | | 2003 | 46.337362681599 | | 2002 | 46.007575130959 | | 2001 | 45.826006505008 | | 2000 | 45.682653731801 | | 1999 | 45.633403394173 | | 1998 | 45.668119022744 | | 1997 | 45.800442985884 | | 1996 | 46.061655150912 | | 1995 | 46.010868105443 | | 1994 | 46.021264049637 | | 1993 | 46.716817599322 | | 1992 | 46.90477853402 | | 1991 | 46.933146838231 |
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