1960

5.0

1985

6.7

1980

6.8

2002

7.9

1972

8.6

2012

4.0

2013

6.8

1994

6.3

1969

7.0

1958

6.7

1974

7.5

1984

8.1

1973

6.9

1989

8.1

1993

0.0

1987

0.0

1997

6.5

2009

7.3

1985

0.0

1999

7.0