1976

5.7

1955

7.2

2005

6.9

1989

7.4

2007

6.1

2008

4.5

2000

6.7

2003

5.5

2002

5.5

2002

7.2

1987

7.1

1990

7.3

1998

6.4

1991

6.9

2009

7.2

2002

6.4

1997

7.6

1968

7.4

1969

7.8