| Year | Value | | 2024 | 20,502,744 | | 2023 | 19,905,091 | | 2022 | 19,339,314 | | 2021 | 18,998,959 | | 2020 | 18,893,273 | | 2019 | 18,684,549 | | 2018 | 18,404,527 | | 2017 | 18,132,886 | | 2016 | 17,912,345 | | 2015 | 17,709,821 | | 2014 | 17,575,548 | | 2013 | 17,397,233 | | 2012 | 17,208,263 | | 2011 | 17,016,358 | | 2010 | 16,848,382 | | 2009 | 16,661,983 | | 2008 | 16,472,578 | | 2007 | 16,296,084 | | 2006 | 16,139,677 | | 2005 | 15,975,662 | | 2004 | 15,822,784 | | 2003 | 15,674,662 | | 2002 | 15,532,792 | | 2001 | 15,360,826 | | 2000 | 15,188,055 | | 1999 | 15,042,362 | | 1998 | 14,920,341 | | 1997 | 14,796,996 | | 1996 | 14,648,447 | | 1995 | 14,497,158 | | 1994 | 14,352,168 | | 1993 | 14,200,363 | | 1992 | 14,053,053 | | 1991 | 13,894,281 | | 1990 | 13,723,253 | | 1989 | 13,520,912 | | 1988 | 13,287,281 | | 1987 | 13,120,761 | | 1986 | 12,950,918 | | 1985 | 12,826,484 | | 1984 | 12,717,147 | | 1983 | 12,606,617 | | 1982 | 12,491,539 | | 1981 | 12,352,193 | | 1980 | 12,208,861 | | 1979 | 12,061,154 | | 1978 | 11,953,673 | | 1977 | 11,848,574 | | 1976 | 11,723,914 |
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