1957

6.4

1997

6.7

2005

7.5

1993

6.5

2005

7.2

1997

5.9

1997

4.5

2017

7.0

1964

7.0

2007

6.0

1995

7.8

2003

5.8

2009

6.1

2005

6.3

1943

6.5

1992

6.1

2002

5.8

2008

6.7

2002

6.2

1999

5.1