1973

5.7

1992

6.8

2012

8.0

2002

6.3

2001

5.8

2006

7.8

1972

6.2

1997

4.4

1987

8.1

1971

6.4

1985

6.4

2007

6.6

2008

7.4

1992

7.4

1986

7.3

1954

8.0

2008

5.5

2000

6.4

2013

7.6

2012

6.3