supply to 17 million exactly
it is not "exactly" 17 million because in all these blocks there has been miners who messed with the code and made mistakes which meant they didn't take the block reward and that reward (that is newly genrated coins are lost forever). lost in this context means out of circulation and never entering it at all.
for example this one:
https://www.reddit.com/r/Bitcoin/comments/7n1ie5/someone_destroyed_125_newly_mined_bitcoins/Out of that 17million mined 10% is held in 'satoshi nakamotos' wallet and a further 4 million bitcoins are lost!!!
it is customary that when you make a guess you say you are making a guess.