1988

6.1

2005

6.4

1999

7.3

2005

6.2

2003

7.0

2007

7.1

1968

7.6

1972

7.1

2001

6.7

2007

6.4

1995

6.7

2000

7.2

1958

6.0

1999

6.8

1982

3.2

2007

6.3

2007

6.7

1989

7.1

2003

8.3

1968

7.1