1988

0.0

1998

4.9

1983

6.4

2006

5.7

1997

5.9

1982

0.0

2006

4.3

2006

5.4

1991

6.3

1986

5.7

1992

7.1

1995

6.5

1987

5.2

1996

6.4

1990

6.5

1996

6.2