1997

6.1

2011

2.7

2014

6.3

1988

7.1

1992

7.1

2004

1.0

1982

4.6

2013

6.7

1986

6.1

2000

6.3

1986

6.7

1999

6.5

2000

7.0

1974

7.0

1984

6.5

1983

5.4

2006

6.2

1980

6.0

2007

1.0

1979

7.2