I cannot find any accurate information with what speed and based on what formula the coins which are not in circulation will be in circulation and when (approximately) all coins will be in circulation.
The formula is quite complex, but at a high level it's an exponential decay like Bitcoin.
Up to 0.3% of the remaining reserves may be mined at each epoch (5 days), however it depends on various factors such as how many blocks were mined, so currently the average is closer to 0.2% per epoch.
At 0.2% per epoch, that corresponds to 13.59% of remaining reserves mined every year:
1 - (1 - 0.002)^(365/5) = 0.1359
So assuming 0.2% per epoch, it would take roughly 16 years (from genesis) for 90% of the supply to be in circulation, and 32 years for 99% to be in circulation.