1981

6.7

1989

5.8

1986

6.2

1999

6.8

2000

5.0

2003

4.9

2006

5.6

1988

0.0

2005

6.3

2000

6.8

2008

5.4

2009

6.0

1999

7.3

1973

3.1

1981

5.9

1980

4.3

2020

6.3

1987

5.2

1997

6.2

1968

6.5