“…Furthermore, the impact of personal income is examined by analyzing poverty rates [16,56,57,66] or income quintiles [10,35,40] in addition to the traditional measure of per capita income. Other measures are population proportions of demographic characteristics, such as educational background [10,12,34,35], gender [33,43], single motherhood [5,10,48,52,57,66], age [10,24,52], and race [10,12,33,35,36,46,47,52,57]. Some researchers have also examined the political orientation of public sector [10,16,35,36,52,62].…”