• 1973 to 1974 1
• 1975 to 1979 5
• 1980 to 1984 5
• 1985 to 1989 4
• 1990 to 1994 9
• 1995 to 1999 14
• 2000 to 2004 29
• 2005 to 2009 46
• 2010 to 2014 63
• 2015 to 2017 23