2007

3.5

1970

4.5

1999

3.8

1991

4.0

1999

4.9

2003

5.7

1997

6.0

1957

7.1

2000

5.6

1984

6.2

1971

2.0

2001

0.0

1990

6.9

1955

6.0

1975

5.7