1981

6.1

2015

8.1

2011

9.1

2018

6.8

1957

6.9

1987

6.5

2006

7.1

1990

7.3

2019

7.0

2020

5.9

2018

5.9

1939

7.9

1979

6.7

2019

5.6

2021

7.8

1971

6.5

2010

6.7

2006

6.4

2002

5.5

1950

6.8