1984

4.3

2001

5.7

1981

4.9

1979

5.9

1998

5.9

1974

4.1

1977

4.6

1989

4.5

1985

3.8

1991

5.3

1993

6.3

1997

4.2

2008

4.0

2007

4.5

1974

4.2

1972

10.0

2006

5.5

2012

5.0

2004

7.3

1991

0.0