1991

6.7

2003

5.5

1995

6.8

1957

7.0

1978

6.3

1992

5.2

1943

6.9

2007

5.8

1989

7.0

2003

7.2

2004

7.8

1958

6.3

1968

6.0

2002

6.2

1983

4.1

1998

6.3

1997

5.7

2009

5.7

1983

5.4

2007

7.2