1960

7.6

1998

7.0

1995

8.0

1965

7.0

2007

5.6

1994

6.9

1912

6.3

1931

0.0

2008

5.3

2008

5.7

2002

5.8

1992

4.0

1989

7.3

1931

6.9

2006

4.6

1955

7.2

2001

7.5

2001

6.1

2007

6.0

1964

6.4