1981

5.2

2001

6.2

1996

6.5

1997

5.4

1998

5.0

1994

5.7

2001

3.7

1994

7.0

1997

0.0

1986

5.3

1970

6.1

2009

6.6

1984

5.3

1995

4.6

1990

8.0

1995

7.8