1988

5.4

2009

6.6

2015

4.0

1981

7.3

1997

6.8

1973

5.7

1971

6.6

2008

4.8

2008

6.1

2003

6.4

1987

6.3

2005

3.2

2020

6.3

2014

5.0

2014

3.8

2000

7.3

2005

5.9

2003

6.1

2002

6.1

1989

5.7