1988

5.2

2014

6.5

2023

6.7

2011

5.5

1975

6.9

2010

6.8

2005

6.8

2019

6.7

1976

7.5

1989

5.9

2001

6.2

1974

6.6

1998

6.0

1995

5.6

1995

7.8

1986

5.8

2008

6.3

1992

6.5

2010

6.7

2015

6.5