1997

6.1

2015

5.3

1995

6.5

2017

6.6

2020

6.5

2016

6.5

2001

6.0

2001

7.0

2001

6.8

2013

7.5

1995

5.6

2017

6.5

2013

6.6

2008

7.2

2003

6.3

1980

6.6

2015

6.3

1966

6.2

2016

6.8

1988

5.7