1973

7.5

2008

6.7

1986

6.3

2007

7.1

2008

6.7

2005

7.0

2006

7.0

1984

8.4

1990

7.5

1983

5.9

2002

7.4

1995

6.0

1961

7.2

1952

6.9

1992

5.4

1982

6.4

1995

5.2

2001

7.4

1987

7.1

1953

6.4