1981

5.2

1998

5.2

1988

0.0

1998

2.0

1994

2.3

1999

5.0

1994

7.0

1994

7.2

2001

4.8

1970

6.1

2009

4.1

1999

5.5

2001

4.4

2003

0.0

2000

6.0

1975

4.8

2005

4.6

1992

3.4

1976

5.2