1995

7.8

1987

8.4

2005

5.7

1993

8.1

1955

7.7

1993

7.0

2002

8.3

1998

7.2

2008

7.8

2009

8.0

2011

5.6

2006

8.1

1999

8.4

2015

7.6

2010

6.4

1969

8.2

1967

6.9

2004

5.8

2016

6.1

2008

7.0