2015

6.3

2006

6.5

2003

5.9

2012

4.3

2017

5.6

1975

6.7

2007

5.3

1989

4.0

1996

6.3

1994

6.1

1997

7.0

2005

6.8

1971

7.2

2001

6.1

1985

6.2

1979

2.0

2007

6.8

1994

5.1

1986

6.0

2001

4.7