1992

6.3

1970

5.3

1974

6.2

1981

3.2

1981

6.7

1977

6.8

2004

5.9

1974

6.6

2017

6.0

2003

5.3

2006

6.0

1997

6.1

1971

7.2

2007

6.2

1985

6.7

2005

6.8

1999

6.8

1998

5.8

1997

5.7

1989

5.8