• 1970 to 1974 15
• 1975 to 1979 33
• 1980 to 1984 21
• 1985 to 1989 19
• 1990 to 1994 31
• 1995 to 1999 44
• 2000 to 2004 71
• 2005 to 2009 73
• 2010 to 2014 54
• 2015 to 2015 1