1972

6.2

1984

6.8

2002

6.0

1997

5.2

1984

7.1

1987

7.3

1939

7.6

2021

6.2

2002

7.7

2004

8.0

2005

7.8

2007

7.7

2009

7.7

2015

3.0

1992

7.3

1990

7.0

1946

8.3

1987

5.8

2021

5.9

2012

5.0