1992

7.1

1981

7.0

2007

6.8

2008

7.5

1984

6.5

1981

7.0

2013

6.0

1992

7.1

1999

5.9

1998

6.2

2000

5.1

1989

5.2

2000

5.8

1965

7.9

1929

7.5

2000

6.6

1994

4.6

1960

7.2

2020

6.0

2013

5.8