The results of the 2004 census indicates that only about 15 per cent of foreign workers are in the skilled category, with the remainder mostly working in agriculture, cleaning and domestic service.[19] Country of origin has been an important factor in determining foreign workers' occupational roles in Saudi Arabia. Saudi businesses have traditionally adopted an ethnically defined hierarchical organisation.[20] For example, a recent academic study of a Danish manufacturing company's Saudi subsidiary noted that a manager had to be European, a supervisor had to be Egyptian, Filipino employees often had technical roles, and Indians, the lowest in the hierarchy, worked in production.[20] Foreign workers' presence in Saudi Arabia tends to be transitory: only 3% remain in the country for more than six years.[21]