1997

7.2

2002

6.4

2007

6.1

2018

4.5

1974

4.8

2021

7.5

1948

6.0

1939

5.8

1941

6.2

1983

5.5

1999

6.0

1986

6.8

1994

6.2

1976

7.3

1968

7.0

1996

5.9

1999

5.5

2006

5.6

2003

5.6

1995

6.9