1982

6.2

2004

4.7

1995

6.3

2008

5.3

1969

4.6

2001

7.5

1979

6.0

2001

6.9

1997

6.5

2003

7.2

1999

7.1

1992

7.4

2005

6.2

2006

5.1

2001

6.4

1961

4.6

1974

7.4

1982

6.0

1968

5.5

1969

5.1