2015

5.9

2011

5.6

1988

6.3

1996

5.4

1973

7.5

2014

6.3

7.1

2010

7.2

1968

6.9

1983

5.8

1989

6.2

2007

6.9

1992

6.2

2011

6.9

2004

6.0

2005

5.9

1998

6.8

1979

7.6

1999

5.9

2011

7.5