1987

4.1

2006

6.6

2005

7.1

1971

7.2

2007

6.2

1985

6.7

1998

7.5

1991

6.8

1995

7.3

1991

7.3

1995

6.0

1981

7.2

2007

5.3

2006

6.6

2016

7.0

2011

6.7

2005

7.5

2002

7.5

2006

5.6

1976

7.3