1970

5.6

1989

8.3

1955

7.5

1983

7.2

1979

7.0

1986

7.8

1999

7.3

1956

7.9

1998

4.8

2011

6.0

1996

6.6

2002

7.3

1988

7.8

2002

8.4

2000

7.6

1987

7.3

2002

7.1

1963

5.6

1999

7.0

2004

7.4