Year	Number
1996	1.16952216625214
1998	1.18287515640259
2000	1.16698145866394
2002	1.28276693820953
2003	1.46513116359711
2004	1.40210604667664
2005	1.38492727279663
2006	1.34965407848358
2007	1.34201574325562
2008	1.33847212791443
2009	1.29713952541351
2010	1.27827215194702
2011	1.30248832702637
2012	1.29035115242004
2013	1.28392601013184
2014	1.28659331798553
2015	1.36598539352417
2016	1.38275027275085
2017	1.39288794994354
2018	1.39100873470306
2019	1.57721149921417
2020	1.58857178688049
2021	1.58106744289398
2022	1.58773648738861