1993

6.7

2005

5.6

2010

6.8

2009

6.6

1977

5.3

2005

7.0

1981

5.5

1941

6.6

1999

6.1

1998

6.4

1994

1.0

2014

4.7

1941

7.2

2009

7.0

1999

6.2

1991

6.6

2007

6.2

1951

6.7

2001

5.8

1997

6.8