2004

6.1

2001

4.7

1998

6.5

1996

5.9

2000

6.8

2005

6.0

1986

6.3

1998

5.3

1986

2.0

2002

8.4

1987

6.6

1970

5.9

1974

6.0

1989

7.1

1994

7.8

1997

4.0

2002

6.3

2002

7.3

1998

7.1