For the global economy, notes the just-released 17th annual World Wealth Report from the Capgemini wealth consultancy and the Royal Bank of Canada, 2012 turned out to be one real downer.

“The myriad crises of 2011 cast a shadow into 2012,” the study relates, “and widespread fiscal austerity exerted a palpable drag, resulting in sluggish GDP growth for the global economy throughout the year.”

But the world’s wealthy —the “high net worth individuals” among us — didn’t let this “palpable drag” get them down in the least. Their fortunes soared in 2012.

The analysts at the Capgemini and RBC count anyone with $1 million in investable assets as “high net worth.” They don’t include in this $1 million tally the value of primary personal residences, automobiles and other consumable durables, or jewelry, art, and other collectibles.

By this definition, the new World Wealth Report calculates, global millionaires ended 2012 holding $46.2 trillion in net worth, 10 percent more than the year before — and 14 percent more than the total wealth of the world’s millionaires in 2007, right before the global economic meltdown.

Two key points about this mammoth mountain of assets. The first: The wealthiest of the wealthy — those individuals with over $30 million — make up less than 1 percent of the global high-net-worth population. But they hold over a third, 35.2 percent, of the high-net-worth population’s wealth.

The second: America’s rich continue to outpace the rich anywhere else in the rest of the world. The United States has, for starters, many more high-net-worth individuals than any other country, over three times more than Germany, over five times more than China, over a dozen times more than Switzerland.

The U.S. millionaire population is also growing at a faster pace than millionaire populations elsewhere, with a growth rate nearly triple Japan’s.

And, oh, yes, one more thing: All these numbers on wealth holdings, Capgemini and RBC researchers acknowledge, understate the fortunes of the world’s most financially fortunate. The reason: The wealth the wealthy have stashed in offshore tax havens does not all show up in the new World Wealth Report.

The data in the report, the authors note, do “theoretically” account for offshore investments, “but only insofar” as countries can accurately estimate “relative flows of property and investment in and out of their jurisdictions."

And the world’s offshore tax havens would rather not do that estimating.