Year	Number
1996	1.56321668624878
1998	1.52875912189484
2000	1.53565549850464
2002	1.34559643268585
2003	1.39797866344452
2004	1.45221567153931
2005	1.53229212760925
2006	1.24485528469086
2007	1.29765582084656
2008	1.3171306848526
2009	1.54556608200073
2010	1.58691143989563
2011	1.56395924091339
2012	1.50602972507477
2013	1.48697376251221
2014	1.39577543735504
2015	1.3876895904541
2016	1.25035130977631
2017	1.27913475036621
2018	1.29667818546295
2019	1.22793257236481
2020	1.25917327404022
2021	1.32937872409821
2022	1.37199735641479