In all measured indicators the numerator is the debt service annual amount in current US dollars. Its exact "official" definition runs as follows:
Total debt service is the sum of principal repayments and interest actually paid in foreign currency, goods, or services on long-term debt, interest paid on short-term debt, and repayments (repurchases and charges) to the IMF. Data are in current U.S. dollars. Source : World Bank, Global Development Finance.
The Debt service / total public service salaries (DS/WS) refers to the ratio between the debt service annual amount in current US dollars and total public service salaries during the same year. Total public service salaries are defined as follows:
Salaries (% of total expenditure) consist of all payments in cash, but not in kind, to employees in return for services rendered, before deduction of withholding taxes and employee contributions to social security and pension funds. Data are shown for central government only.
(Source : International Monetary Fund, Government Finance Statistics Yearbook and data files.)
DS/WS = Total debt service (current USD) / [(Salaries (% of total expenditure) / 100) • (Total expenditure (% of GDP) / 100) • GDP (current USD)]
A ratio DS/WS = 0,457 means that the debt service represents 45,7% of the total public service salaries. A ratio DS/WS = 3,487 means that the expenses due to debt service is 3,487 times more important than the total public service salaries.
Mode of interpretation : DS/WS measures the debt service burden in relation to the country’s public service salaries. It shows to what extent the debt service results in civil servants’ redundancies.