1967

5.5

2003

6.8

2005

6.5

2000

6.0

1925

6.9

1995

6.5

1994

8.3

1990

6.1

1980

5.6

1992

6.6

2002

7.0

2002

3.7

1991

6.1

1990

6.1

1990

6.7

1990

6.0

2002

6.2

1981

7.3

2001

5.9

1988

6.2