2001

5.6

2000

7.0

1998

6.9

1981

5.5

1997

8.1

1966

7.6

1983

8.1

2005

7.1

2000

5.6

1966

7.5

1988

7.7

2000

7.6

2001

5.3

2003

7.6

1980

5.8

2000

8.0

1973

6.6

2005

6.0

1974

5.2

1996

7.8