Year	Number
1996	1.46770334243774
1998	1.47467350959778
2000	1.49741804599762
2002	1.4848747253418
2003	1.27146780490875
2004	1.08084416389465
2005	0.966194272041321
2006	1.05953097343445
2007	1.39488196372986
2008	1.42050349712372
2009	1.61128449440002
2010	1.61671948432922
2011	1.6102602481842
2012	1.59499299526215
2013	1.57741558551788
2014	1.73981142044067
2015	1.64631330966949
2016	1.64717769622803
2017	1.63387060165405
2018	1.63483166694641
2019	1.63669180870056
2020	1.71637678146362
2021	1.70454776287079
2022	1.72041630744934