1980

0.0

2014

7.0

2013

7.8

1999

6.9

2012

7.2

1991

5.2

2013

7.5

2010

7.2

1984

8.1

2008

8.5

2012

5.6

2013

6.9

2013

6.0

2001

7.9

1968

7.7

2012

6.1

1994

4.0

1981

5.0

1992

0.0

1987

0.0