1995

6.5

1998

6.6

2005

6.2

2006

6.8

2004

6.2

1991

7.1

1984

7.1

1993

6.2

1975

8.4

1975

7.3

2006

6.6

2018

6.3

2020

6.3

1981

5.0

1957

4.6

1996

6.6

2003

7.8

2002

7.0

1990

7.8

2004

7.3