1995

7.8

2001

5.6

1985

6.7

1988

7.1

2002

7.6

1999

6.1

1975

7.3

2000

8.0

1985

8.3

9.2

1987

8.2

1960

7.4

2003

6.2

1988

7.7

1999

7.7

1993

6.8

1989

6.8

2004

8.0

2004

5.3

1985

6.3