1983

7.9

2011

5.7

1999

7.4

2015

6.7

1993

8.0

2004

5.9

2002

6.6

1985

6.5

1984

7.7

1988

6.9

2013

7.2

2003

6.2

2000

6.4

2008

6.8

1977

8.2

1989

6.6

2009

5.6

2006

7.8

1987

6.7

1997

4.6