1967

5.5

2003

6.8

2005

6.5

2000

6.0

1995

6.5

1994

8.3

1980

5.6

1997

5.7

2002

7.0

1990

6.1

1990

6.7

2002

6.2

2001

6.8

1978

6.3

1988

6.2

1996

5.4

1928

0.0

1996

6.2

1997

6.3

1998

6.8