1991

0.0

1989

7.8

1998

8.3

1997

7.9

1995

8.1

1955

3.5

2001

5.6

2007

8.1

1995

6.3

1984

6.0

2002

6.9

2007

6.6

1941

6.6

1963

7.6

2009

6.4

1991

6.4

2020

6.2

1994

6.0

2010

6.7

2015

7.0