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 5500 2001 22000 2002 34200 2003 65000 2004 123000 2005 210000 2006 466088 2007 918356 2008 1600000 2009 2281320 2010 2875304 2011 3665661 2012 4402282 2013 4561243 2014 5251560 2015 5465797 2016 5585709 2017 6368600 2018 6984130 2019 7664839 2020 8687151 2021 10346160 2022 12086643