1992

6.2

1982

6.7

1975

6.3

2002

2.0

2001

7.8

1994

7.0

1983

5.9

1999

7.0

2005

6.8

2006

7.1

1999

7.8

2003

7.2

1991

6.2

1995

6.2

1993

6.3

2002

5.7

1997

7.8

1994

5.8

1993

5.0

1997

6.9