2002

4.3

2001

5.7

1990

6.1

1994

6.0

1995

7.4

1998

7.1

1987

6.1

1994

5.2

1979

6.7

1995

4.9

1993

7.0

1995

7.8

2007

0.0

1976

7.5

1981

6.7

1987

8.4

1995

7.8

2000

7.0

1998

5.3

1999

7.7