The source adds further comments: "Wealth data are good in the high-income countries (...) The reliability of the source material differs among the countries discussed. For each country, data quality is rated as no worse than “fair,” meaning that there is at least some credible source of data on wealth, such as a recent household survey. In most of the selected countries quality is “good,” indicating that there is an official household sector balance sheet as well as an acceptable way to estimate wealth distribution."