1993

6.9

1996

7.2

2003

7.7

2005

7.5

1999

8.0

1994

8.3

2005

6.1

1991

6.6

2007

6.5

2000

7.1

2004

7.2

1982

6.3

1982

6.7

1960

7.7

1970

3.2

2014

2.3

1987

6.7

2016

7.3

2021

6.1

2004

6.9