1998

6.0

1988

7.4

2001

9.9

2010

5.8

2020

6.3

1991

5.9

2003

6.5

1989

5.3

2007

6.2

1995

6.2

2013

8.5

2006

6.7

1997

5.7

2003

7.3

1993

6.2

2006

5.5

1985

6.1

2002

7.4

2007

4.6

2011

5.7