1978

3.8

2014

6.4

1972

2.7

1989

4.3

1997

3.7

1977

2.3

2009

5.5

2008

5.9

2006

5.2

2008

4.8

1999

6.6

1991

5.3

1986

5.5

1993

6.3

2004

5.2

1998

5.7

2003

5.0

2000

6.8

1970

3.0

1973

5.7