1987

7.0

2011

6.0

1987

5.1

2007

7.5

2002

6.0

1998

6.6

2005

6.8

2006

5.6

2008

4.3

2007

6.9

1991

6.6

2000

5.2

1999

6.7

2017

5.6

2017

6.8

2004

6.4

2003

6.1

1993

7.4

1992

7.2

2001

6.3