1992

6.3

1974

6.2

1973

4.8

1981

6.7

1977

6.8

1996

6.8

2004

5.9

1972

6.7

1989

5.8

2017

6.0

2003

5.3

2017

6.2

2006

6.0

2003

7.2

1971

7.2

2004

7.0

1985

6.7

1982

6.9

1985

7.1

2005

6.8