1992

7.1

2003

6.7

1987

6.5

1997

7.1

1999

6.0

1999

6.6

1994

5.7

2004

5.5

2009

5.5

1998

6.2

2006

6.0

1971

7.7

2004

5.3

2006

6.4

2004

6.5

2001

5.7

1965

6.0

1999

3.4

2017

6.5

1990

6.4