Year	% of total teachers
2006	74.2045211791992
2007	72.509147644043
2008	69.4115371704102
2009	65.0847396850586
2010	66.5127410888672
2011	62.9700088500977
2012	64.3291778564453
2013	59.8681793212891
2014	58.3227195739746
2015	57.9442710876465
2016	58.8758697509766
2017	58.3965606689453
2018	59.1380805969238
2019	58.1217193603516
