Yes, it's such a messy thing. At the very beginning, one of Evan's ideas / worries was that maybe people would stop mining because the rewards are not profitable. So Xcoin or Darkcoin started life with an algorithm that would cause the rewards to be larger if the hash rate was low, and lower if the hash rate was high and healthy with a minimum payout of 5 dash. In fact, this little algorithm is what caused the "instamine" along with the general flaw of Litecoin/Bitcoin and all coins based on POW, which has rewarded early miners with the most coins. It simply made it worse. I am sorry, but I can't find the original algorithm??
Anyway, next, Evan received pressure to limit the number of coins. Since this could be done for the "future" and would have no ill effect on anyone, he decided on the 7% reduction per year (approximately) which is a smoother reduction than that of Bitcoin, which halves every 4 years. but gives similar results. Even then, he didn't think the hash rate would stay up high enough to pin the rewards to the minimum, but it did. We stuck to minimum since early on.
So, now it's even more complex. With 10% of the rewards going to budget items, and any unused funds never being created, PLUS the 5 dash it costs to make a budget proposal being destroyed, it cuts the circulation down even more.
So I don't even know if the coinmarketcap.com has an accurate measure of coins (does it included removal of "burned coins" from the total?) And a long time ago when I was guesstimating how many coins we'd end up with, I came up with something closer to 14.5-15 million coins. But these guys are smarter than I am, so I'm sure they're more accurate

Then again, we average only 550 blocks a day calculated, instead of 576, which is what we would have if we actually had a block every 2.5 minutes, But since the reward reduction happens every X blocks (576 x 365 = X) That probably doesn't matter in calculating "final number of coins" But keep in mind that this is going to go on basically forever, with rewards halving forever.
Anyway, I hope the history clears things up. Even so there is this algo that increases rewards if the hash rate drops, it's unlikely to ever drop low enough to increase the rewards ever again. I think my baikal miner might be enough to keep that from happening today, LOL. So you can safely ignore it.