1959

6.9

2000

6.4

1991

5.5

2004

5.6

1973

7.5

2020

8.2

1984

10.0

1997

6.1

2006

6.7

2017

6.8

2017

6.6

1973

0.0

1932

6.0

1999

0.0

1988

8.0

1990

7.7

1987

0.0

1963

0.0

2007

5.0

1968

7.6