FRANKFURT (Reuters) - The number of fake euro banknotes is on the rise, the European Central Bank (ECB) said on Thursday, with the 50 euro note the preferred choice of counterfeiters.

The ECB said the number of fake euro notes seized by authorities had jumped more than 15 percent in the first six months of the year.

A total of 312,000 dodgy notes were taken out of circulation in the first half of 2008, the highest since 2003 and up from 265,000 in the first half of 2007.

The ECB said 36 percent of all seizures were 50 euro notes, 33 percent were 20's and 21.5 percent of recoveries were 100 euro notes.

The Frankfurt-based central bank estimates that there are around 11.5 billion legitimate euro notes if circulation following its introduction in 2002.

It revealed on Wednesday that as much of 20 percent of all euro notes are in countries where it is not even legal tender.

"When the figures...are compared with the number of genuine euro banknotes in circulation, the quantity of counterfeits is very small indeed," the ECB said.

Current Euro members:

Country	Flag	Euro	Rate	Abbreviation
Austria		Yes	13.7603	ATS
Belgium		Yes	40.3399	BEF
Denmark		No		DKK
Finland		Yes	5.94573	FIM
France		Yes	6.55957	FRF
Germany		Yes	1.95583	DEM
Greece		Yes	340.750	GRD
Ireland		Yes	0.787564	IEP
Italy		Yes	1936.27	ITL
Luxembourg		Yes	40.3399	LUF
Netherlands		Yes	2.20371	NLG
Portugal		Yes	200.482	PTE
Spain		Yes	166.386	ESP
Sweden		No		SEK
United Kingdom		No		GBP