Hey it's written in the on post, but it's not a fixed rate since  pump and dump occurs at any stages even to the Bitcoin.

During the first year it is estimated from $0.01 to $0.10  per 1 SINT and in 10 years $100 = 1 SINT per year. Investing early will make us more profits, but we need to be patience while investing.

May be they can offer another bonus during crowdsale, presale and in ICO.