1987

7.3

1990

7.5

2001

6.1

1954

7.2

1999

6.8

1964

7.4

1974

7.2

1970

7.1

1987

7.0

1942

7.0

2005

6.2

2002

6.8

2004

7.9

1995

7.7

1994

8.0

1998

6.6

2002

7.8

1973

6.9

2007

6.4

2009

6.8