Year	% of population
2001	2.644353136669641
2002	2.606840818539416
2003	2.587205608264753
2004	2.5749191510515845
2005	2.564460781738686
2006	2.566054272527389
2007	2.5609138955893815
2008	2.551678082699411
2009	2.5430623162460324
2010	2.543826448661193
2011	2.556547927693709
2012	2.5508274859055726
2013	2.545958875254137
2014	2.549012462373622
2015	2.5473393589870734
2016	2.5425408875327578
2017	2.523623457574323
2018	2.512588123712381
2019	2.503584368046095
2020	2.5017823276208113
2021	2.5078488397631706