Year	% of total teachers
2007	78.7022399902344
2008	78.3855361938477
2009	75.637321472168
2010	76.1671371459961
2011	73.5893707275391
2012	74.0146102905273
2013	70.2985000610352
2014	68.0941009521484
2015	68.4132919311523
2016	68.2747497558594
2017	66.9546279907227
2018	68.2156295776367
2019	67.6737670898438
2020	66.927619934082