1966

7.3

2020

5.0

1967

6.0

2000

5.0

1998

6.7

2005

6.0

1993

6.2

2003

5.8

1999

7.5

1996

8.0

2001

7.0

2000

5.9

1997

7.4

1998

5.9

1980

6.4

1986

7.6

2002

7.2

1999

6.8

1993

5.0

2006

6.6