Year	Number
2004	3.0678567111393833
2005	2.185385235296953
2006	2.843255924492771
2007	4.550518837564103
2008	3.459833105682163
2009	3.178858223206366
2010	2.8884805556603066
2011	2.118843019573046
2012	3.2012491071919427
2013	3.144560648806842
2014	2.4017031826870627
2015	2.7303276336806457
2016	2.1406263439272633
2017	2.4937339956475353
2018	2.2615128569184395
2019	2.528223706106758
2020	3.033863043234844
2021	2.3700288442409754
2022	2.168127517600736
2023	1.946090075073373