You have to wait exactly one year for 100% interest.
So, it's wrong what "NeuBuy" said?
"You'll also have a lot of uncertainty, if you're unlucky it could be years before you mint coins." And if it's wrong, why did Sandrine say: "What @NeuBuy posted is a good explanation of what the Growth Account is."?
Edit Source:
http://forum.neucoin.org/t/investors-in-neucoin-growth-account/1341/6