Year	Number
1996	1.44895005226135
1998	1.35477888584137
2000	1.31755948066711
2002	1.30749690532684
2003	1.34388208389282
2004	1.47565114498138
2005	1.37865650653839
2006	1.37268495559692
2007	1.36926245689392
2008	1.35846436023712
2009	1.39284467697144
2010	1.43029069900513
2011	1.40244364738464
2012	1.44877302646637
2013	1.45656740665436
2014	1.3913494348526
2015	1.3835529088974
2016	1.33747661113739
2017	1.38591921329498
2018	1.39915668964386
2019	1.33687436580658
2020	1.39443778991699
2021	1.38676011562347
2022	1.40876078605652