1987

6.9

1979

6.3

1981

6.0

2004

7.2

1993

7.3

1996

7.3

2006

6.5

2001

7.0

2004

6.0

2004

6.8

2007

7.3

2016

6.1

1999

6.3

1992

5.6

1981

6.4

2006

6.8

2004

6.6

2006

6.8

1976

6.6

1999

6.2