1984

6.2

1998

8.2

1990

7.3

2006

5.1

2001

6.2

1991

8.1

1999

6.7

1986

6.9

1991

4.7

1994

4.8

1977

7.2

2005

5.4

2000

4.8

2009

6.5

2008

4.7

2013

6.3

1945

6.0

2007

5.3

2014

3.1

2010

6.4