1955

7.1

1978

7.2

1987

6.4

1983

5.7

2018

7.5

2002

8.4

2007

5.6

2003

5.7

2011

6.5

2004

6.0

1991

6.3

2010

6.1

2010

6.7

2007

6.3

1991

5.3

2009

6.7

2013

6.0

1985

6.2

2013

5.7

1980

6.7