1999

6.8

1998

6.6

1993

5.5

1982

5.2

1995

6.7

2002

7.2

2006

6.0

2001

7.3

1984

5.9

1997

6.7

1963

4.5

2005

6.7

2005

6.9

2001

7.4

1991

5.8

1989

7.0

1995

6.5

2003

6.4

1990

6.8

1994

7.0