Year	Number
2006	12.474848158549982
2007	13.68434635862375
2008	10.98729574220701
2009	14.547026525891818
2010	11.746972451321946
2011	6.647795323182553
2012	8.55745154197407
2013	9.263539162942338
2014	11.803141595801767
2015	9.606117244165773
2016	9.43703232126754
2017	9.885724663037879
2018	7.897478269944921
2019	9.985645573253128
2020	12.530395080288692
2021	9.736952267029535