Year	number
2005	29.11764705882353
2006	29.235294117647058
2007	29.352941176470587
2008	27.294117647058822
2009	27.470588235294116
2010	27.470588235294116
2011	27.529411764705884
2012	29.11111111111111
2013	29
2014	29.05
2015	28.55
2016	26.25
2017	24.95
2018	24.7
2019	24.05