1969

6.5

1999

5.5

1971

5.2

1969

4.1

1977

5.6

2007

5.9

1995

3.8

2003

7.8

2009

7.5

1988

7.1

1976

5.6

2001

5.1

2004

5.5

1960

6.1

1993

7.7

2002

5.5

1968

7.6

1975

5.5

1984

5.0

2005

6.4