1988

6.3

1994

5.8

1997

7.0

1991

8.1

1995

7.0

1994

5.9

2003

7.7

1990

7.5

2004

7.9

2001

6.4

1970

6.1

2023

5.0

2007

7.2

2005

7.5

1980

5.2

2007

6.5

2001

5.9

1999

6.8

1994

5.8

1997

6.8