1996

5.0

2007

5.6

1990

6.9

1978

5.9

1993

7.7

2010

8.0

1987

5.4

2002

6.5

2009

7.9

2002

7.9

1984

7.5

1987

3.8

2009

8.0

1972

3.3

1989

5.0

1999

8.2

2006

7.3

2008

7.6

2011

6.0

2005

7.5

1997

4.7

1998

5.6