1990

4.7

1945

7.7

2004

7.3

1970

7.0

2007

6.2

1997

7.0

1939

7.6

2007

6.1

1998

6.4

2005

7.4

2001

5.9

2006

7.0

2003

7.2

2005

5.1

1966

6.7

2016

5.9

1982

7.2

1996

6.8

1973

8.0

1964

5.0