Year	% of total teachers
1999	51.7404289245605
2000	51.4327011108398
2001	53.0699691772461
2003	57.4748382568359
2005	57.2046089172363
2007	57.27294921875
2008	58.4919090270996
2009	63.6986312866211
2010	66.0630111694336
2011	67.696907043457
2012	69.6494216918945
2013	76.8219985961914
2014	77.7200012207031
2015	77.0859985351562
2016	78.6900024414062
2017	78.6100006103516
2018	76.9540023803711
2019	75
2020	68.3160018920898