1987

7.8

1990

7.7

2006

7.5

2002

6.7

1971

7.5

2004

7.2

2003

7.1

2005

7.1

2020

2.0

1937

5.0

1954

8.5

2014

4.9

2008

5.7

2007

4.0

1938

7.0

2008

6.4

2012

10.0

2011

8.2

1996

5.9

2007

6.3