United states is number one, China is number ten, Russia is number twenty nine, and Germany is number eight. It means you're wrong if you think strong economy countries aren't in debt.
Debt isn't always bad for filthy rich people or countries, watch Robert Kiyosaki how he use debt to make more money and protect his wealth.
Debts do not represent a problem if you can print money or obtain larger grace periods. In the end, all countries deal in dollars and are forced to accept them. The debts of the United States, China, and even the G20 countries do not represent problems for them because they are able to deal with them politically, and no country may think of waging wars. Because of its debts.
Medium and poor countries are the ones that suffer from the costs of debt, especially medium and poor societies, which bear most of these debts, either directly in the form of interest or indirectly, such as inflation, which makes life more difficult.