1981

0.0

1977

4.7

1978

7.2

2004

6.0

1995

6.5

2002

5.6

2010

6.6

2017

7.8

1991

6.7

1988

6.7

2003

6.3

1993

7.4

1978

6.2

1992

6.2

2003

7.0

1960

6.9

2006

5.0

2006

5.6

2010

6.5

1987

7.3