1979

6.7

2008

7.0

1974

6.5

1996

5.9

2008

6.3

1955

7.2

1972

7.4

2010

6.4

2012

7.3

1983

6.1

2017

6.0

2003

7.5

2018

6.0

2012

8.2

1986

5.8

2005

5.7

2013

7.6

1973

5.7

1971

6.4