1992

6.7

1987

3.7

2004

6.8

1990

7.4

2001

8.5

1998

7.1

1994

7.0

2.0

1986

7.2

1982

3.5

1999

7.5

1998

7.7

2004

6.3

1986

6.0

1994

7.8

2007

7.9

2002

7.3

1995

7.0

1993

7.7

2004

5.9