根据国家统计局的数字,2009年度全国农民工总量为2.3亿人,受户籍、住房、教育等约束,许多农民工不得不把家人留在农村,自己单枪匹马到城市闯荡。一方面在农村形成了一个以妇女、儿童和老人为主体的留守群体,造成农村人口在年龄结构上的极不合理分布。一方面由于城乡二元 According to the figures of the National Bureau of Statistics, in 2009, the total number of migrant workers nationwide was 230 million, constrained by household registration, housing and education. Many migrant workers had to leave their families in rural areas and go solo on their own. On the one hand, a left-behind group mainly composed of women, children and the elderly has been formed in rural areas, resulting in an extremely unreasonable distribution of age structure of the rural population. On the one hand because of urban and rural duality