1967

6.9

1993

7.5

2006

5.0

1987

7.3

2007

6.0

2001

5.2

1983

6.6

1970

7.5

1997

5.1

2003

5.9

1996

6.9

1988

6.9

1997

6.2

2006

6.3

2007

6.7

2014

6.8

2005

5.7

2004

5.5

1978

7.4

1966

6.2