1980 2,368 1,704

1981 2,692 1,870

1982 2,676 1,978

1983 2,882 2,181

1984 3,203 2,391

1985 3,295 2,457

1986 4,010 2,803

1987 5,325 3,511

1988 6,337 4,686

1989 7,577 5,737

1990 8,178 6,516

1991 9,092 7,523

1992 10,726 8,002

1993 11,201 8,741

1994 12,109 10,206

1995 13,076 12,333

1996 13,597 13,138

1997 13,968 12,132

1998 12,787 8,085

1999 13,768 10,409

2000 14,877 11,948

2001 13,408 11,256

2002 13,716 12,789

2003 14,094 14,219

2004 15,361 15,922

2005 16,503 18,658

2006 16,985 20,917

2007 17,781 23,102

2008 18,103 20,475

2009 16,960 18,339

2010 19,262 22,151

2011 20,912 24,156

2012 21,270 24,454

2013 21,874 25,975

2014 22,598 28,101