Year	Number
1996	1.542760014534
1998	1.37591946125031
2000	1.4047327041626
2002	1.31849634647369
2003	1.3334413766861
2004	1.36798417568207
2005	1.31246471405029
2006	1.42389464378357
2007	1.4855865240097
2008	1.50248491764069
2009	1.42739927768707
2010	1.41517114639282
2011	1.44053530693054
2012	1.53619813919067
2013	1.48287189006805
2014	1.48458957672119
2015	1.31984269618988
2016	1.36390829086304
2017	1.32520079612732
2018	1.30045235157013
2019	1.15849316120148
2020	0.948647737503052
2021	0.936240255832672
2022	0.978411138057709