Year	%
2000	3.761564067436982
2001	3.6042385976678686
2002	3.4859064006144496
2003	3.307228472158704
2004	3.1445368753755676
2005	3.0242821156617707
2006	2.8751899345404603
2007	2.8021435988193235
2008	2.697521285288112
2009	2.5781442052840893
2010	2.445991464402374
2011	2.3384241641035906
2012	2.18215200031068
2013	2.079407316525676
2014	1.9938105567227273
2015	1.9101872462200853
2016	1.8075490388212982
2017	1.7247276382041883
2018	1.638444099178395
2019	1.5777318811268044
2020	1.5191885759556203