2003

6.2

1983

7.9

1990

7.4

1999

8.4

1990

6.3

2000

6.4

1971

6.4

1998

6.0

2008

6.3

2005

7.7

1995

7.3

1974

8.6

2003

5.3

1981

6.6

1987

6.5

1988

6.9

2004

5.9

2013

7.6

1970

6.1

2012

6.3