1980

4.3

2003

4.9

1987

4.8

1995

5.8

1992

6.8

1984

6.0

1968

6.5

1973

3.1

2000

5.0

2005

6.3

1997

3.5

2013

3.2

1993

10.0

1968

0.0

1991

5.2

2005

5.2

2007

8.0

1993

5.8

2007

4.7

2001

6.2