1969

3.8

1986

4.5

2008

5.7

1993

3.0

2007

6.0

1973

6.4

2007

5.4

1999

5.5

1998

6.3

1974

5.1

1985

6.6

1995

4.9

2006

5.2

2010

4.8

1999

4.8

2006

4.8

2010

5.9

1962

0.0

1999

5.8

2004

5.8