1987

6.8

1996

5.9

2005

7.3

1995

6.7

1980

6.7

1998

6.3

2001

6.1

1976

7.3

2003

6.6

1956

6.9

1963

7.2

1973

6.7

1996

6.2

2002

5.8

1955

6.0

2009

5.4

2021

6.1

1964

6.1

2017

6.8

1981

5.4