1995

8.0

2005

5.7

1990

7.7

2002

7.2

1980

6.7

2005

4.5

1986

7.7

2004

7.5

2003

8.3

1980

8.2

1968

7.1

1978

7.5

2004

7.1

2007

5.6

2006

7.0

1991

8.3

1999

7.5

1984

7.3

2001

7.4

1996

7.4