1968

6.7

2004

8.0

2002

7.1

1991

6.6

1999

6.8

2004

6.3

2005

8.1

2003

5.3

1977

6.5

1993

7.7

2004

6.8

1960

6.5

2001

6.8

1991

7.4

2006

5.8

2003

7.3

1987

7.3

1965

6.4

2002

6.8

2004

10.0