Year	Number
2007	7.311747051033457
2008	4.714851116572751
2009	9.310147618101702
2010	7.8657357144662425
2011	7.314451848220649
2012	7.174976665909402
2013	7.034019923032668
2014	5.425658770713443
2015	5.850065101668436
2016	5.238607867690084
2017	4.959309588727792
2018	4.678012112007986
2019	5.179583822446611
2020	6.13291553531939
2021	5.2524575148864265
2022	4.83595341885135
2023	6.179346245397824