Compared to the micro-census , families with adolescents ( 8.2 % vs. 16.9 % ; p < 0.001 ) and single parents ( 16.0 % vs. 23.3 % ; p < 0.005 ) were underrepresented in the study population , whereas families living in rural areas were overrepresented ( 58.7 % vs. 50.2 % ; p < 0.005 ) .