1968

6.8

2019

6.7

1989

5.5

2002

5.0

1978

5.9

1990

6.1

1998

6.0

2004

7.2

1982

5.9

1992

6.5

1987

6.3

2015

6.5

1997

6.0

1986

6.3

1920

7.3

1966

6.2

2020

6.4

2005

6.8

1940

6.2

2003

6.8