EUR/USD: 28 %
USD/JPY: 18 %
GBP/USD (also called sterling or cable): 14 %
and the US currency was involved in 88.7% of transactions, followed by the euro (37.2%), the yen (20.3%), and the sterling (16.9%) (see table). Note that volume percentages should add up to 200%: 100% for all the sellers and 100% for all the buyers.
Although trading in the euro has grown considerably since the currency's creation in January 1999, the foreign exchange market is thus far still largely dollar-centered. For instance, trading the euro versus a non-European currency ZZZ will usually involve two trades: EUR/USD and USD/ZZZ. The exception to this is EUR/JPY, which is an established traded currency pair in the interbank spot market