Disposable Income refers to the sum of final consumption expenditures and other non-compulsory expenditure that is the freely disposable household income. It is that the total income minus personal income tax paid by the individual contribution to social security spending and subsidies investigations households accounting income. The formula is: Disposable income = total household income - pay personal income tax - personal contribution to social security spending - accounting subsidies. Data on income and expenditure of Urban Households are obtained from the sample survey on urban households. ||Since 2002, the objects of urban households survey are changed from non-farm households to households in the district areas of all city and county towns. ||All households in the sample are grouped, by per capita disposable income of the household, into groups of lowest income, low income, lower middle income, middle income, upper middle income, high income and highest income, each group consisting of 10%, 10%, 20%, 20%, 20%, 10% and 10% of all households respectively. The lowest 5% of households are also referred to as poor households.