Subsistence data may have to be developed through surveys, although the SLiCA survey does provide some data on indigenous households for the regions of Canada, Chukotka, Alaska, and Greenland. These data are available for the survey year only. Across the Arctic nations, the North is primarily a sending region, that is, more people leave northern regions than move there. Migration affects the number of people living in a region. It also influences the demographic structure of a place, since the propensity to migrate differs across demographic groups (Hamilton and Seyfrit, 1994). Sometimes a move is for a short period of time to secure training or education, this human capital investment allows the migrant to return home to improved job prospects.