Year	% of population
2008	19.3593967858844
2009	22.9495292787135
2010	18.232328746577
2011	21.5577640428023
2012	21.2934392583388
2014	18.5345715932081
2015	20.2980670188729
2016	21.3509334308074
2017	20.6508227803182
2018	18.867371775192
2019	17.5655595444711
2020	18.8505505680402