Tracking the rich has become a voyeuristic global industry, a form of celebrity worship. But it can also provide serious clues about where countries are headed.

When a country begins to fall into economic and political difficulty, wealthy people are often the first to ship their money to safer havens abroad. The rich don’t always emigrate along with their money, but when they do, it is an even more telling sign of trouble.

Since 2013, New World Wealth, a research outfit based in South Africa, has been tracking millionaire migrations by culling property records, visa programs, news media reports and information from travel agents and others who cater to the wealthy. In a global population of 15 million people each worth more than $1 million in net assets, nearly 100,000 changed their country of residence last year.

In most countries it is fair to assume that any millionaire exodus is composed mainly of locals, and not foreign investors, because the wealthy classes will be dominated by citizens or longtime residents. In 2017, the largest exoduses came out of Turkey (where a stunning 12 percent of the millionaire population emigrated) and Venezuela. As if on cue, the Turkish lira is now in a free fall. There were also significant migrations out of India under the tightening grip of its overzealous tax authorities, and from Britain under the cloud of Brexit.