1995

6.8

2006

6.1

1974

6.9

1985

5.3

2007

6.2

1993

6.5

1996

5.3

2006

8.3

2000

6.2

1997

8.1

1966

7.6

1983

8.0

1963

7.9

1966

7.5

2006

7.5

2003

6.6

1974

6.4

1987

7.8

1996

7.2

1999

6.8