Year	% of population
2006	40.3956270045321
2009	37.3166595988828
2011	37.4848520174713
2012	36.6384289104755
2015	38.5397194467505
2016	39.4683612044082
2017	40.471803466109
2018	40.0811524884081
2019	39.3039679076058
2020	35.6270860683671