1982

7.6

2004

7.9

1993

7.7

1994

8.4

2005

8.1

1997

4.6

2000

8.5

1987

7.7

2009

7.9

2009

7.5

1995

7.2

1996

7.8

2001

6.4

1984

6.1

1998

7.2

1990

6.9

2011

5.0