1979

6.1

2011

7.1

1998

5.5

1995

7.3

2010

7.7

1977

6.8

2002

7.0

1990

7.4

2000

6.8

2010

7.0

2014

7.8

2007

7.4

2003

6.1

2006

7.6

1938

7.1

2014

6.5

1985

6.2

2006

7.8

2008

6.5

2005

6.8