Year	Number
1996	1.50620913505554
1998	1.48220026493073
2000	1.45910060405731
2002	1.66384208202362
2003	1.65858423709869
2004	1.55899655818939
2005	1.60670387744904
2006	1.3497759103775
2007	1.37826728820801
2008	1.39858841896057
2009	1.5131573677063
2010	1.52523505687714
2011	1.49699103832245
2012	1.5524400472641
2013	1.57182216644287
2014	1.4229462146759
2015	1.37643611431122
2016	1.36056172847748
2017	1.4847491979599
2018	1.52256798744202
2019	1.52985751628876
2020	1.62055170536041
2021	1.52809131145477
2022	1.62934851646423