| Year | Value | | 2023 | 21,842,876 | | 2022 | 21,511,126 | | 2021 | 21,191,985 | | 2020 | 19,406,591 | | 2019 | 20,607,477 | | 2018 | 20,103,008 | | 2017 | 19,580,710 | | 2016 | 19,404,277 | | 2015 | 19,229,476 | | 2014 | 19,049,721 | | 2013 | 18,964,106 | | 2012 | 18,835,226 | | 2011 | 18,663,922 | | 2010 | 18,255,867 | | 2009 | 18,324,357 | | 2008 | 17,966,575 | | 2007 | 17,924,078 | | 2006 | 17,877,291 | | 2005 | 17,545,905 | | 2004 | 17,425,150 | | 2003 | 16,951,795 | | 2002 | 16,491,672 | | 2001 | 16,651,214 | | 2000 | 16,588,444 | | 1999 | 16,410,324 | | 1998 | 16,307,035 | | 1997 | 15,992,986 | | 1996 | 15,563,537 | | 1995 | 15,201,443 | | 1994 | 15,067,090 | | 1993 | 14,697,546 | | 1992 | 14,275,486 | | 1991 | 13,867,845 |
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