The stock of national debts is used to reflect the proportional relationship between the accumulative amount of national debts and economic aggregate in the same year, so it is also called "debt-to- gross domestic product (GDP) ratio". While the accumulative amount of national debts is not large, the issuing scale and growth rate are on the high side. In fact, national debts in China are issued as fiscal revenue financed by the Central Government, which is included in the central budget, scheduled and used by the Central Government. The high degree of fiscal expenditure's dependence is the result of the large issuing scale of national debts. The principal and interest on national debts have to be repaid. In case of fiscal difficulty, especially of central fiscal difficulties, when the peak of debt repayments arrives, the government is forced to borrow new debts to repay the old ones in order to deal with the exchange of matured national debts.