Year	% of total teachers
2009	70.3834991455078
2010	68.6335830688477
2011	64.6631469726562
2012	64.3437271118164
2013	62.1846809387207
2014	57.6520385742188
2015	57.7425117492676
2016	62.1437911987305
2017	62.5782089233398
2018	65.7049331665039
2019	61.1922912597656