1980

6.7

2005

6.5

2001

6.0

2006

4.3

1973

6.5

1978

6.2

2014

5.5

1989

6.1

2004

6.4

1997

6.6

2019

7.0

2006

6.5

1995

6.4

1996

5.7

2014

3.5

1997

5.5

1971

7.1

1993

4.5

2006

3.4

2007

5.8