1979

6.8

2009

8.5

2013

7.0

1987

7.2

2007

4.0

2002

7.4

1988

5.7

1992

5.3

1981

6.6

1980

0.0

1986

4.0

1999

7.0

6.3

1993

7.4

1999

7.5

2005

7.4

2002

8.2

2006

7.1

1990

7.1

2001

8.0