Year	% of total teachers
2006	77.6458282470703
2007	74.307487487793
2008	68.8094787597656
2009	65.7101821899414
2010	62.9597587585449
2011	55.3674087524414
2012	60.2375984191895
2013	55.1004104614258
2014	56.7844085693359
2015	57.6827201843262
2016	61.6037712097168
2017	62.3290100097656
2018	64.3274612426758
2019	61.2857398986816