1974

6.8

1998

5.7

2003

6.4

1988

6.5

2017

6.5

2001

6.0

1969

7.8

2007

6.7

2012

7.0

2007

6.8

1993

6.2

2004

6.4

1997

7.1

1964

6.0

1989

7.6

2006

6.5

1994

6.5

1977

0.0

1998

7.1

1988

6.6