1999

7.0

1988

8.1

2000

8.0

2016

8.2

2020

8.1

2007

7.2

1997

8.3

2012

7.6

1998

7.0

2002

7.3

2002

7.7

2006

7.5

2019

7.6

2009

8.3

2015

7.4

1978

7.1

2013

7.9

2020

8.5

2008

7.6

2014

6.9