• 1987 to 1989 9
• 1990 to 1991 5
• 1992 to 1994 14
• 1995 to 1996 12
• 1997 to 1999 13
• 2000 to 2001 1
• 2002 to 2004 6
• 2005 to 2006 5
• 2007 to 2009 9
• 2010 to 2011 0
• 2012 to 2012 1