1985

6.7

2005

6.5

2000

7.2

2014

4.5

2021

4.7

2000

6.3

1992

7.0

1974

7.5

2000

6.8

1977

6.7

1992

6.6

2002

6.7

1981

6.5

1986

6.2

2004

7.9

1970

7.5

2003

7.1

1975

6.1

2001

5.8

2004

6.6