1997

5.6

2001

6.0

1987

6.5

1999

6.9

1994

7.6

2007

5.0

2008

5.8

1998

6.2

2007

6.2

2004

6.5

2019

4.8

1980

6.0

2008

5.8

1970

6.4

2005

5.9

1972

7.3

2008

5.4

2005

7.0

2001

6.3

1977

6.3