1999

7.4

2003

5.8

2004

5.6

1987

7.3

1963

5.0

2001

6.5

2002

5.3

2005

6.3

2004

6.7

1988

7.1

2002

4.8

1992

6.3

2007

5.9

2003

4.3

2002

6.2

2008

5.8

1997

6.1

1989

6.3

2001

6.4

1977

6.2