if all the coins were mined then it would be correct. But it's basically how many coins have been mined to date.

Bitcoin for example right this second has 12 million+ bitcoins in circulation. but a total of 21 million will be mined in the future. You work out the total by the amount of coins currently in existence. not how many there are going to be. unless they have all already been mined.

 icoin i think will have 17.5 million in the first year in circulation, so any estimation of price should be using that number as a basis of value....Althou that number could be slightly wrong. i read it from a fellow Icoiner and didn't check the accuracy.

But it will take 900 years to have the total number of coins in circulation