The debt-to-GDP ratio is the standard measure of a sovereign’s obligations against the economy that must service them. A rising ratio means debt is growing faster than the tax base claiming it.

$$ \text{Debt-to-GDP}=\frac{\text{general government debt}}{\text{GDP}}\times 100 $$

The data is the Bank for International Settlements (BIS) long total credit to general government series as a percentage of GDP, in US dollars, quarterly. It covers loans and debt securities owed by the whole general government sector, including state and local government, divided by nominal GDP. Using the series directly means no currency conversion and a consistent definition across all four countries.

Japan stands out, with general government debt around twice its GDP. Italy and Greece sit above 150 percent in longer European data. Germany and Australia sit at the disciplined end of the range. China’s ratio has climbed sharply since the 2008 stimulus, and the United States has been trending steadily higher since the 1980s.

• United States: BIS QUSGAN770A
• China: BIS QCNGAN770A
• Japan: BIS QJPGAN770A
• Germany: BIS QDEGAN770A
• United Kingdom: BIS QGBGAN770A
• India: BIS QINGAN770A
• Australia: BIS QAUGAN770A
• Frequency: Quarterly. US from 1947, UK 1966, India 1981, Australia 1988, Japan 1997, China 1995, Germany 2000