1978

7.6

2000

4.7

1998

6.8

1992

7.0

2003

6.1

2004

6.0

2006

7.8

2006

6.0

1993

5.9

1991

0.0

2012

6.5

2008

7.2

1997

6.0

1985

10.0

2003

7.6

2001

4.6

2009

7.3

1988

6.3