Year Number 1985 9500 1986 9000 1987 22000 1988 22000 1989 22300 1990 22300 1991 22300 1992 22300 1993 22300 1994 22300 1995 22300 1996 23000 1997 24600 1998 24500 1999 33500 2000 35054 2001 35054 2002 34496 2003 35680 2004 40076 2005 43282 2006 47585 2007 50440 2008 51921 2009 50716 2018 36660 2019 41933 2020 20703 2021 28019