1990

7.8

1994

7.4

1980

6.0

1988

5.2

1993

7.4

2001

7.5

2013

5.3

2018

6.7

2006

8.2

1962

7.9

1952

5.3

2020

6.8

1939

7.2

1946

7.4

2002

7.3

2014

6.5

2007

5.8

2008

5.9

2014

6.4

2003

6.3