1997

6.0

1971

7.2

2014

5.9

2013

6.1

1983

5.7

1961

6.9

1993

6.2

2008

7.0

1993

6.5

2013

4.0

2009

5.8

2015

4.6

1965

6.8

2008

6.3

1970

6.3

2007

4.9

1987

5.5

1966

6.8

1977

5.4

2011

6.2