1997

6.5

1986

4.6

1988

6.3

2006

8.2

1994

7.8

1981

5.6

2004

8.6

1979

6.8

1992

6.7

2000

8.5

2002

7.9

2002

6.0

1995

6.6

1978

5.6

2009

7.3

1987

5.3

1997

7.7

1999

8.3

2003

6.0

2002

7.3