Outbound travelers from four major Asia Pacific markets accounted for close to one-fifth of global travel spending last year, highlighting the region's burgeoning tourism appetite, according to a new report by financial services firm, Mastercard.

Overnight visitors from mainland China, South Korea, Japan and Taiwan made up 18.5% of global travel spend within the world's top 200 cities in 2018 — up from 11% a decade earlier, Mastercard's new "Global Destination Cities Index: Origins" study found.

The report, which draws on data from third-party sources including the World Travel & Tourism Council, examined the total number of international overnight visitor arrivals in 2018 to find the world's leading outbound travel markets. It comes as part of wider Mastercard research into the global travel industry, set to be released later this year.

The U.S. continued to contribute the greatest number of overnight international arrivals to the top 200 cities in 2018, accounting for 9.9% of the global total. However, the Asia Pacific region saw significant uptick over the past decade, the report found.