1987

7.3

1970

7.1

1997

6.3

2006

7.4

1998

6.4

2005

7.5

2001

5.9

2006

7.0

2003

7.2

1995

6.6

1967

7.6

2001

6.8

2003

5.6

2008

5.5

1973

0.0

2004

7.3

2014

7.2

1973

7.2

1939

7.6

2007

6.1