1981

7.2

2002

1.0

2005

8.2

1999

7.6

2003

8.5

1993

7.0

1985

7.8

2004

5.5

1990

8.3

1964

7.5

1971

7.8

1988

5.8

1966

6.1

2000

7.7

2004

10.0

1962

6.9

2005

7.6

1974

5.8

1995

6.2

1985

6.7