1997

3.7

2008

4.8

1998

5.7

2004

3.6

2003

4.4

1991

0.0

2000

6.3

2014

5.7

1988

7.1

1992

6.3

2016

4.5

2015

5.4

1990

5.7

2007

2.4

2001

3.5

1999

3.0

1973

5.2

1979

6.4

1971

6.6

2010

2.5