1977

0.0

2003

7.4

2008

8.5

2002

6.6

1994

6.2

1990

7.7

1961

7.6

1980

6.6

2001

7.2

1982

6.4

1988

7.5

1991

7.3

2006

5.8

1989

6.0

1997

7.4

2006

7.5

2001

6.8

1986

7.5

1995

7.9