1991

2.4

2011

4.3

1992

6.4

1988

5.9

2000

8.0

2009

5.9

1995

7.4

1986

5.4

2004

6.3

1993

7.0

1987

7.7

1988

6.9

1989

7.8

1990

7.9

1993

0.0