1997

4.5

2003

5.2

2011

5.5

2017

4.7

1994

5.8

1998

8.0

1987

5.7

1994

7.0

1986

5.4

2007

0.0

2014

0.0

1970

6.1

2001

6.6

1997

5.6

1987

0.0

1992

3.4