1988

6.7

1991

7.5

2005

6.7

1960

6.4

2006

7.0

1994

5.9

2005

6.9

2003

6.7

1965

6.3

2002

7.0

2003

6.0

1999

4.5

2002

5.9

2003

7.5

1991

7.5

2005

7.3

2004

6.8

1999

7.5