Year	% of total teachers
2007	64.1559219360352
2008	59.5134391784668
2009	59.1862487792969
2010	53.255989074707
2011	47.707160949707
2012	54.6738090515137
2013	55.8404006958008
2014	63.3210182189941
2015	66.5556411743164
2016	72.4605331420898
2017	76.9966430664062
2018	76.3485565185547
2019	72.3878173828125