1977

6.6

1974

6.6

2009

7.2

1973

6.7

1979

4.8

2001

6.1

2004

6.6

1972

7.7

1966

7.3

1999

7.0

2006

6.0

2006

5.8

1997

7.5

1991

6.2

1994

5.8

1993

5.0

2000

5.7

1989

6.6

1989

6.8

2007

5.8