1978

5.0

1996

6.1

2000

6.5

2006

6.3

1977

6.0

1971

7.0

1997

5.9

1983

6.8

2008

6.7

1977

5.6

2009

5.9

1995

7.8

2002

3.4

1996

6.3

2006

7.1

2017

5.1

1985

7.6

2005

6.2

2008

3.2

2008

5.7