Global wealth skyrocketed 8.3 percent over the past year to a record $263 trillion, but the distribution of the riches has also become increasingly unequal, a Credit Suisse report said Tuesday.

With the increase from mid-2013 to mid-2014, global wealth now stands 20 percent above the peak before the global financial crisis and a full 39 percent above the low seen at the height of the crisis in 2008, according to the Swiss banking giant's "Global Wealth Report."

"The overall global economy may remain sluggish, but this has not prevented personal wealth from surging ahead during the past year," the report said.

The study, which comprises the wealth holdings of 4.7 billion adults across more than 200 countries, showed that aggregate household wealth has more than doubled since the beginning of the millennium, when it stood at just $117 trillion.

And over the next five years, global wealth is expected to balloon by another 40 percent to $369 trillion, it said.

Today, each adult globally has an average of $56,000 — an all-time high for average net worth, according to the report.

But while average net worth has surpassed its pre-crisis high by 7.0 percent, the median wealth has plunged 14 percent since 2007 to $3,641 per adult.

The decline in the median — the level at which half of the sample is lower and half higher — indicates that inequality, which remained flat or declined from 2000 to 2007, is once again on the rise, the study said.

"The findings show that inequality has tended to rise since 2008, particularly in developing economies," Markus Stierli of the Credit Suisse Research Institute said.

The study said most of the rise in wealth over the past year can be credited to North America, which accounts for 34.7 percent of global household wealth, and Europe, which accounts for 32.4 percent.

Both regions showed hikes of about 11 percent.

In contrast, Latin America saw little change, while China recorded only a small rise of around 3.5 percent, and India saw its wealth fall one percent, the study said.

On a country level, Britain, South Korea and Denmark recorded the largest percentage gains, while Ukraine, Argentina and Indonesia saw the largest losses, it said.

Switzerland meanwhile maintained the highest average wealth per adult, at $581,000, followed by Australia, Norway, the United States and Sweden.

As a sign of wealth concentration, the number of dollar millionaires globally has shot up 164 percent since 2000 to 34.8 million individuals today — a full 41 percent of them living in the United States, the study showed.

Some 128,000 of the world's millionaires have assets of at least $50 million, with nearly half of them living in the United States and nearly a quarter in Europe.

Credit Suisse said it expected the number of global millionaires to exceed 53 million in 2019, with the number in China expected to nearly double from its 1.18 million today.

Some one billion people meanwhile belong to the global middle class, with wealth ranging from $10,000-100,000, the study showed.

China's share of the middle class has doubled since 2000 and now accounts for one-third of people in that category, it said.