Year	Number
1996	1.55714535713196
1998	1.56213402748108
2000	1.5439612865448
2002	1.4694139957428
2003	1.52679491043091
2004	1.69660830497742
2005	1.66602003574371
2006	1.53982102870941
2007	1.52343332767487
2008	1.48308551311493
2009	1.46438777446747
2010	1.45056891441345
2011	1.5370477437973
2012	1.60558545589447
2013	1.56697261333466
2014	1.5473108291626
2015	1.56116330623627
2016	1.54033207893372
2017	1.49597573280334
2018	1.49929475784302
2019	1.48340129852295
2020	1.51986396312714
2021	1.49022936820984
2022	1.54186487197876