1981

5.2

1997

4.5

2000

5.0

2010

7.4

1998

0.0

1994

1.0

2011

0.0

2000

5.6

1986

5.9

2013

6.0

1994

7.0

2011

7.0

1996

6.5

2001

7.3

1971

6.4

2017

7.2

2007

6.1

1970

6.1

1999

5.5

1995

5.0

1992

3.4