Year Number 1960 0 1965 0 1970 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 0 1981 0 1982 0 1983 0 1984 0 1985 0 1986 0 1987 0 1988 0 1989 0 1990 0 1991 0 1992 0 1993 0 1994 0 1995 0 1996 0 1997 0 1998 5000 1999 11000 2000 39000 2001 65000 2002 82391 2003 130720 2004 137271 2005 222978 2006 314201 2007 635137 2008 1322637 2009 2429252 2010 3548761 2011 4446194 2012 5690751 2013 6689158 2014 7747019 2015 8759619 2016 8921533 2017 8819217 2018 9700609 2019 9658548 2020 10614408 2021 10902989 2022 11002078