1973

4.8

1977

5.0

1977

5.6

1995

3.3

2014

6.4

2008

6.0

2002

4.3

1997

6.2

1983

5.1

1999

6.0

2003

6.7

2002

5.3

2007

6.6

2017

4.6

1988

6.3

1977

4.5

1974

2.8

1971

5.2

2000

3.0

1984

4.8