Year Total 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 20 1998 1020 1999 8068 2000 19729 2001 31507 2002 42949 2003 53342 2004 65780 2005 81721 2006 108858 2007 152212 2008 277670 2009 290621 2010 371871 2011 396429 2012 425310 2013 499458 2014 613378 2015 611468 2016 601956 2017 612259