1990

6.4

2008

7.3

1996

6.3

2002

7.3

2007

7.2

2005

6.4

2005

7.3

2004

5.7

1991

6.7

1997

6.2

2006

7.1

2007

5.1

1958

7.2

1993

6.9

1977

5.6

1987

8.1

1995

7.4

2004

6.4

2003

7.5

2017

6.0