1989

7.2

1999

7.7

2002

8.4

1993

8.6

1955

7.3

1956

7.1

1957

7.2

2000

7.4

1994

7.5

1989

8.3

1986

7.9

1972

8.7

1974

8.6

1982

7.6

1970

7.0

1987

7.6

1990

8.5

1973

1.0

1996

6.6

2004

7.9