1998

4.9

2012

6.9

1988

5.3

2004

5.8

1986

6.5

2011

7.1

1996

6.7

1975

7.2

2012

6.0

1982

6.2

2009

7.4

2012

5.5

1995

6.5

1996

5.8

2008

4.6

1979

7.6

1989

5.1

2016

7.0

2016

5.9

2025

5.8