2001

6.8

1990

6.1

1980

6.8

2006

5.1

2003

5.8

2012

6.1

2010

6.6

1991

5.9

2002

9.1

2007

7.5

2013

7.5

1994

7.4

1984

9.2

2011

5.5

2005

6.0

1988

7.5

2007

5.4

2005

4.9

1971

7.7

1986

6.5