1997

6.5

1999

5.6

1998

6.5

2018

6.7

1999

6.8

2004

7.5

2000

6.8

1981

0.0

2002

6.1

2007

8.1

2005

5.9

2007

7.1

1998

6.6

2006

5.8

2007

6.1

2009

7.1

1958

7.2

1998

7.2

2006

7.1

2003

7.1