1979

9.8

1986

6.7

1991

7.7

1996

6.6

1996

7.1

2003

5.3

1998

7.9

1953

7.2

2003

6.3

2007

5.9

2004

6.5

1990

6.7

1988

6.3

1995

6.2

2005

6.2

2001

5.4

2002

5.8

2003

7.8

2006

6.5

1981

7.1