2002

6.6

2004

6.4

2001

6.1

2005

6.7

1999

6.8

2020

6.4

1997

6.2

1975

6.3

1974

5.9

2003

6.8

2006

7.6

2005

5.4

1993

6.7

2000

6.0

2004

6.0

1997

6.5

1988

7.3

2006

5.1

2002

7.0

2000

6.6