2008

6.8

2008

5.8

1980

6.7

2000

6.4

1990

6.1

1998

6.1

1998

7.1

2003

6.0

1983

5.5

2004

7.3

1990

6.4

1999

6.0

1990

6.0

1978

6.3

1991

6.2

1988

6.2

1984

6.1

2003

5.7

1994

5.2

1996

5.4