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 0 1999 0 2000 0 2001 0 2002 0 2003 0 2004 20000 2005 40438 2006 61996 2007 84348 2008 108631 2009 141130 2010 185275 2011 241939 2012 305283 2013 354844 2014 417400 2015 475000 2016 506000 2017 695000 2019 1311000 2020 1801000 2021 1801000