1979

5.6

2011

6.6

1995

5.8

2005

6.3

1968

6.6

2017

5.1

2007

7.3

2000

6.3

2016

4.6

1973

6.8

1987

7.7

1941

5.8

2004

6.7

1964

7.4

2002

6.7

1961

6.8

1978

4.2

1981

7.1

1997

6.9

1987

6.2