What is the BLEU score used in Google Brain's “Attention Is All You Need” paper?

Question

Google Brain's Attention Is All You Need paper on sequence-to-sequence translation reports:

Our model achieves 28.4 BLEU on the WMT 2014 Englishto-German translation task, improving over the existing best results, including ensembles, by over 2 BLEU

but the Wikipedia entry on BLEU says:

BLEU’s output is always a number between 0 and 1

What definition of BLEU is the Google Brain paper using? I could not find a separate definition in the paper itself.