Which of the following sites should you use when trying to find country-level data on household income?

1. World Bank: The World Bank provides a wealth of information on various economic indicators for countries around the world, including household income. You can access this data through their website's data section.

2. Organisation for Economic Co-operation and Development (OECD): The OECD also provides a wide range of statistics on its member countries, which includes data on household income. This information can be accessed through the OECD's online data library.

3. United Nations Statistics Division: The UN Statistics Division provides a variety of data, including information on household income. This data can be accessed through their website.

4. National Statistical Offices: Most countries have a national statistical office that collects and publishes data on various aspects of the country's economy, including household income. The website of these offices is a good place to look for this information.

5. International Monetary Fund (IMF): The IMF also provides data on a variety of economic indicators for countries around the world, including household income. This data can be accessed through the IMF's website.

Remember to check the methodology used by each site to ensure the data is comparable.