Correct to doubt it, jake. I have been cheerfully citing this bold '100 per cent' because I read it in some article, which I'm pretty sure was in Wikipedia a while ago. If so, it cannot be found by me now. It was probably edited out as wrong, and/or was misunderstood by me in the context of a paragraph with the words 'on current trends, it is expected that' or some such. GM production is certainly on the rise but it still represents,on latest figures available, a small percentage of overall EU production, which is nearly all for animal feed. France, in particular, has a very low production. Spain, on the other hand, seems quite keen on it. [From various EU and EU sponsored sites and French Wikipedia (!)]
Even the figure for the US is not 100 per cent yet. Latest figure is 85 per cent for the total crop, but, of course, it may be that the 15 per cent is not in exports.