2001

5.5

2019

4.8

2009

6.0

1999

5.1

2004

3.8

1990

6.4

1995

5.9

1980

5.9

2002

5.5

1989

6.0

2000

4.6

1991

5.8

1981

5.2

1987

5.1

1992

5.0

2013

1.5

2011

3.7

2010

5.7

1998

5.8

2000

2.7