By the end of 2015, there were around 187,500 ultra-high-net-worth people worldwide, a 3% drop from the 193,100 a year earlier, according to the Wealth Report released by real estate consultancy Knight Frank on Tuesday.

The report laid the blame for the decline squarely on the drop in worldwide commodity prices and volatility in global equity markets, leading the consultancy to conclude that the growth of ultra-high-net-worth individuals is set to slow down in the next 10 years.

The drops were most keenly felt in Latin America and the Caribbean, whose ranks dropped 9% from 2014 to 2015. Countries like Brazil, Venezuela, and Iran saw some of the most drastic drops in the ultra-rich, as the oil price slump seems to have hit those with deep pockets. In the U.S., the number declined about 2%.

“Sharp falls in the oil price also had a notable effect on the ultra-wealthy in many Middle Eastern and some African countries,” said Andrew Amoils, the head of research at wealth intelligence company New World Wealth, who provided the data for the report.

This has led to an increase in the worries over the global economy, with the report showing that 61% of respondents to the study saw the worldwide economic slowdown as a risk to wealth creation for the next 10 years. Other issues that dominated the minds of respondents included “stock market volatility” (which 51% saw as a key risk for the next 10 years) and “succession and inheritance issues (which 67% saw as a future concern for the next decade).