| Year | Value | | 2023 | 20,772,739 | | 2022 | 20,225,443 | | 2021 | 19,773,332 | | 2020 | 19,232,661 | | 2019 | 18,560,826 | | 2018 | 17,735,236 | | 2017 | 16,811,020 | | 2016 | 15,919,658 | | 2015 | 15,063,574 | | 2014 | 14,251,105 | | 2013 | 13,627,526 | | 2012 | 13,190,799 | | 2011 | 12,809,858 | | 2010 | 12,493,226 | | 2009 | 12,238,402 | | 2008 | 12,038,950 | | 2007 | 11,868,283 | | 2006 | 11,685,544 | | 2005 | 11,467,930 | | 2004 | 11,216,554 | | 2003 | 10,929,734 | | 2002 | 10,616,545 | | 2001 | 10,307,873 | | 2000 | 10,018,390 | | 1999 | 9,736,228 | | 1998 | 9,449,589 | | 1997 | 9,163,497 | | 1996 | 8,883,652 | | 1995 | 8,613,236 | | 1994 | 8,352,969 | | 1993 | 8,104,252 | | 1992 | 7,868,920 | | 1991 | 7,646,717 | | 1990 | 7,437,794 | | 1989 | 7,243,811 | | 1988 | 7,066,552 | | 1987 | 6,902,631 | | 1986 | 6,745,645 | | 1985 | 6,592,284 | | 1984 | 6,442,372 | | 1983 | 6,293,867 | | 1982 | 6,148,650 | | 1981 | 6,014,303 | | 1980 | 5,893,142 | | 1979 | 5,782,641 | | 1978 | 5,684,840 | | 1977 | 5,590,864 | | 1976 | 5,476,911 | | 1975 | 5,331,266 | | 1974 | 5,158,089 |
|