It's worth remembering that Suzuha comes from the future, but she only knows what is known by people in the future α world line. In fact, some of that turns out not to be entirely correct, or at least it's misleading.
In any case, it depends on what you mean by "future". Two different futures can have the same, or very close, divergence numbers. This is evidenced by the fact that Mayuri died in many different ways, yet the divergence number didn't change (at least not appreciably). While these are different futures in the near term, they all converge to the same end result, at least as long as they are still on a world line close to the α (alpha) world line. This is what is meant by the Attractor Field.
The divergence number measures how much the world line has deviated from a particular value. To reach the β (beta) world line, they need to get to a divergence number between 1% and 1.99%, and again there's an attractor field so that any world lines in this range converge to the same eventual future. There are also γ, δ, and ω world lines in the visual novel and drama CDs, and of course the
Steins Gate world line.
As for the particular values for divergence number, many are present. The divergence meter has been shown to change by as little as 0.000001%, which would allow for at least 100,000,000 world lines, and for all we know these numbers were just approximate anyway so there could be infinitely many (since they are only quoted to that many significant digits). We can't really say for sure either way, but most of those world lines end up being very close to each other in the end.
From the above link, the known values are:
Divergence numbers are unknown for the δ world line.
.275349 (said to be negative, so maybe it's actually -.275349)
And the spoilery one:
So, depending on how you look at it, there are lots of possible futures (maybe infinitely many), but eventually all of them converge to one of these 6 (as far as we know). There could be more that are revealed later, but based on what is known right now, these are the only 6 possible long-term futures.