1979

8.0

2006

6.9

1994

7.4

2007

7.1

2014

4.2

1999

6.0

1987

6.5

2007

5.0

1967

7.6

2003

6.4

2004

7.2

1996

5.4

1991

8.3

1993

8.1

1998

6.2

2009

6.0

1966

7.6

1954

6.0

1985

7.4

2017

6.6