1993

6.5

2007

7.4

2002

6.5

1980

6.9

2020

5.5

2011

6.7

2006

6.1

1989

6.2

2003

7.1

1988

5.7

2011

6.6

1999

7.3

2006

6.1

1940

8.3

1981

7.1

1989

7.0

1998

7.2

1988

6.3

1996

6.5

1971

6.0