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 1000 1998 3390 1999 5000 2000 70000 2001 150000 2002 221800 2003 330000 2004 383653 2005 558192 2006 917499 2007 1287631 2008 1807000 2009 2948304 2010 3718748 2011 3884757 2012 4283134 2013 4659762 2014 4930100 2015 5216000 2016 5424000 2017 5056000