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 204 1993 457 1994 812 1995 1442 1996 3096 1997 4734 1998 5048 1999 5307 2000 5600 2001 55085 2002 100000 2003 149300 2004 175000 2005 247478 2006 404345 2007 800371 2008 1166136 2009 1312874 2010 1478347 2011 1401163 2012 1526191 2013 1848854 2014 2283691 2015 2715672 2016 2838127 2017 2966000 2018 3181393 2019 2584714 2020 2677954 2021 2677954