1998

3.8

1977

4.6

1997

5.9

1993

3.8

1993

4.4

2009

6.0

1974

6.4

1980

2.8

1999

2.8

2006

4.6

1977

4.1

1995

4.6

1981

4.3

1976

4.3

1977

5.3

1975

5.0

1978

4.9

2003

7.7

2000

4.8

1985

2.0