Year	Number
1996	1.49763286113739
1998	1.43456733226776
2000	1.35786831378937
2002	1.30454540252686
2003	1.40957999229431
2004	1.46491122245789
2005	1.43030512332916
2006	1.23266172409058
2007	1.23142063617706
2008	1.20186388492584
2009	1.12824237346649
2010	1.10720300674438
2011	1.10791051387787
2012	1.02852833271027
2013	1.06693470478058
2014	1.10747110843658
2015	1.12869608402252
2016	1.1576681137085
2017	1.19820749759674
2018	1.17851006984711
2019	1.19467461109161
2020	1.25567591190338
2021	1.24693858623505
2022	1.25333595275879