1967

6.5

1972

6.4

1966

6.3

1989

5.1

2012

6.4

2006

6.7

2008

6.2

1996

5.7

2009

6.6

1994

5.9

2010

7.4

1986

6.8

2014

7.7

1964

7.4

1965

8.0

1987

5.5

2017

6.0

2016

6.4

1986

5.8

1968

6.9