1980

5.8

1973

5.7

1972

7.2

1967

5.7

1967

7.1

2005

6.5

2008

6.3

1993

4.0

2005

0.0

2007

8.1

1964

5.0

2006

6.8

1992

7.0

1978

0.0

2003

5.0

1996

6.0