1982

6.1

1985

5.4

1991

7.1

1986

4.6

1994

7.4

1987

7.1

2009

5.8

2008

6.6

1999

6.8

1984

6.2

1985

7.8

2003

6.8

1969

7.3

1980

5.8

2007

5.6

2005

7.2

2004

4.8

2008

5.6

1995

6.3

1999

5.3