• 1988 to 1989 1
• 1990 to 1991 1
• 1992 to 1994 1
• 1995 to 1996 0
• 1997 to 1999 0
• 2000 to 2001 0
• 2002 to 2004 4
• 2005 to 2006 6
• 2007 to 2009 7
• 2010 to 2011 3
• 2012 to 2013 3