1964

7.2

1972

7.6

1979

7.5

1979

5.3

2002

6.5

1943

6.5

1997

5.8

1992

6.1

2008

6.7

2002

5.8

1986

7.1

2004

6.8

2018

5.2

2002

6.2

2007

7.6

1940

7.1

2003

5.3

2007

6.0

2009

6.6

2009

6.2