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 1990 0 1996 1200 2002 8000 2007 20700 2008 23000 2009 47031 2010 47524 2011 46597 2012 48703 2013 53406 2014 54764 2015 57195