Year	Number
2008	2.178984865038373
2009	2.5732578894518694
2010	2.8457992253804885
2011	3.6861293670721693
2012	2.7281060954373584
2013	3.309903172412587
2014	3.8863627435090766
2015	3.495905628967223
2016	4.587967319473357
2017	3.875425148162401
2018	4.071349376887923
2019	3.96398548019648
2020	4.102839133961706
2021	4.19804043154492
2022	4.156491904959103
2023	4.765139564915583