1992

4.4

2005

5.7

2006

5.5

1999

5.1

1969

5.0

2007

6.0

2004

5.9

2001

5.4

1999

6.7

2007

5.2

2003

3.5

2003

7.5

1991

7.5

1976

0.0

1988

1.0

1993

7.6

1975

5.5

1968

5.8

2010

6.3

1958

0.0