Trading is down 18.9% from the first half of last year, according to statistics reported by members of the World Federation of Exchanges. All told, $26.4 trillion worth of shares changed hands, nonetheless.

Of the three regions of the world tracked by the WFE, the Americas fared best. Volume at North and South America member exchanges was down 14.3% and accounted for half the world volume, at $13.8 trillion.

The decrease in trading volumes in the Americas region was “further pronounced by a 25% drop in number of trades,’’ the WFE said.

Faring the best was BM&BOVESPA in Brazil, down just 1.1%. Nasdaq OMX Group came in at -9.5% down. NYSE Euronext at 18.1% down.

Direct Edge and BATS Global Markets statistics are not gathered by the WFE.

The dollar volume of trading fell 21.5% in Europe, Africa and the Middle East. Trading in Asia and the Pacific region fell 22.5%.

The total market capitalization of companies listed on WFE exchanges increased by 5.3% in the first half of 2012, however, the trade group said. But capitalization remains below the level of one year ago.

Bond trading on exchanges declined for the second consecutive half-year, at 9.3% down, the WFE said. That represented trading worth $14.2 trillion. The European – Asia – Middle East region led the decline at -11.0%, while bond trading in the Asia-Pacific region increased 24.4%.

Trading of exchange-traded funds in the Americas also plunged, by 33.7 percent. That led to ETF turnover of $4.0 trillion in the first half. The Americas region represents more than 88% of total WFE turnover in ETFs.

The 18.9% plunge in trading, worldwide, actually is a slight improvement. After the first three months of 2012, trading was down 19.4%, year over year.