2008

6.6

1998

6.2

1996

5.7

1998

5.7

1995

6.2

1996

6.8

1993

6.8

1998

6.5

1985

7.1

1986

7.0

2002

6.2

1999

5.1

1973

7.4

1992

7.4

2002

6.7

1996

5.6

1991

6.1

2002

5.7

2002

5.4

2001

5.9