1979

7.3

1990

5.5

2002

7.4

2018

6.7

2003

5.2

1959

7.0

2013

6.8

2010

6.1

1998

6.8

1998

8.2

2009

6.5

2005

7.4

1994

7.5

1994

7.1

2012

6.2

1998

6.9

1981

6.4

2014

6.5

2012

6.4

2014

7.9