| Year | Value | | 2023 | 21,639,790 | | 2022 | 21,362,740 | | 2021 | 20,960,467 | | 2020 | 20,471,068 | | 2019 | 20,758,436 | | 2018 | 20,344,108 | | 2017 | 20,144,985 | | 2016 | 19,877,599 | | 2015 | 19,690,129 | | 2014 | 19,586,757 | | 2013 | 19,522,293 | | 2012 | 19,316,264 | | 2011 | 19,146,806 | | 2010 | 18,985,430 | | 2009 | 18,787,385 | | 2008 | 18,662,575 | | 2007 | 18,382,598 | | 2006 | 18,035,498 | | 2005 | 17,819,057 | | 2004 | 17,673,742 | | 2003 | 17,463,547 | | 2002 | 17,068,694 | | 2001 | 16,585,664 | | 2000 | 16,308,539 | | 1999 | 16,041,716 | | 1998 | 15,760,787 | | 1997 | 15,520,772 | | 1996 | 15,278,818 | | 1995 | 15,119,721 | | 1994 | 15,013,489 | | 1993 | 14,871,263 | | 1992 | 14,782,203 | | 1991 | 14,803,644 |
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