1988

5.2

2012

7.3

2014

6.6

2018

6.0

1994

4.4

2016

5.9

1986

5.8

2016

7.7

1973

6.5

1963

7.0

2005

6.0

1956

6.6

1999

6.1

2009

7.5

1989

7.9

2007

6.3

2013

7.5

1972

7.7

2011

7.1

2017

7.7