The number of billionaires in the world surged and their wealth soared to record levels last year, research company Wealth-X said in its new report.

Billionaire population increased by 15 percent to 2,754 individuals, surpassing the previous peak of 2,473 in 2015, while their wealth rose by 24 percent to a record level of $9.2 trillion.

The report attributes this significant increase in wealth to a synchronized upturn in the world economy and climbing equity markets.

In Chinese mainland, the wealth of billionaire swelled by 61.2 percent to $1.08 trillion, accounting for a 12 percent share of global billionaire wealth, up from 9 percent two years ago. The number of billionaires rose by more than a third to 338.

New York, with 103 billionaires, was the world's top billionaire city in 2017, followed by Hong Kong (83) and San Francisco (74).

Beijing recorded the second-largest increase in billionaire population after Hong Kong, adding an additional 19 individuals last year. Its total of 57 billionaires is now ranked sixth among the world's top 10 billionaire cities.

Shenzhen, South China's Guangdong province, tied with India's Mumbai for the ninth place. The number of billionaires rose to 39, underlining Shenzhen's reputation as one of the world's most dynamic and prosperous urban centers.

Led by China and India, the total billionaire population in Asia now stands at 784 individuals, overtaking North America (727) for the first time, according to the Wealth-X Billionaire Census 2018.