1999

3.7

1995

6.7

2002

7.2

1994

7.0

2005

6.8

2006

7.1

1999

7.8

2003

7.2

2001

6.7

2006

6.3

1999

6.8

1998

6.6

1988

5.0

1972

3.7

1987

7.3

1994

5.8

1992

0.0

1995

5.8

1975

4.3

1988

5.6