1987

7.2

1984

7.6

1991

6.4

2005

3.7

1997

6.4

1989

5.9

2.0

2007

5.0

1999

6.7

2002

5.7

1985

6.4

1986

6.9

1994

7.4

2002

7.1

1999

6.8

2003

6.9

1998

6.3

1988

7.0

2007

5.6

1999

5.0