1986

6.1

1992

7.1

2000

6.9

2003

5.1

1984

7.5

1969

6.8

1999

7.5

1998

6.4

1997

7.5

2004

5.2

1972

6.1

1968

5.4

1991

5.7

2006

7.1

1990

6.5

1974

6.9

1976

6.8

2006

6.1

1999

6.8

1962

7.3