Year	Number
1996	1.35965430736542
1998	1.31323409080505
2000	1.44685900211334
2002	1.45780158042908
2003	1.37511277198792
2004	1.36038255691528
2005	1.37716245651245
2006	1.30128657817841
2007	1.34741532802582
2008	1.36263751983643
2009	1.45200526714325
2010	1.47382998466492
2011	1.51992893218994
2012	1.55911040306091
2013	1.60430264472961
2014	1.51295030117035
2015	1.47469651699066
2016	1.53148806095123
2017	1.40388441085815
2018	1.42942035198212
2019	1.44899594783783
2020	1.44595634937286
2021	1.45552504062653
2022	1.49504864215851