1981

6.5

2010

6.4

2001

6.1

1941

7.1

1998

5.9

1971

6.4

1982

5.7

2010

7.8

1995

5.7

2003

4.0

2014

5.6

2000

7.2

1988

5.8

1991

6.9

1990

6.5

2010

6.0

1967

6.6

2007

6.0

2014

7.6

2003

6.2