According to several online sources, BTC reached the level of being 85% mined on August 1st. This means that there are under 3,15 out of 21 million coins left to be mined. With that being said, there are over 17,85 million coins currently circulating in the BTC market, which means that they mined 85% of BTC in 10,5 years.
Some people think that mining the remaining 15% will take just a couple of years. However, this will not be the case. They say that the last Bitcoin will be mined in 120 years, sat some point around 2140.
This will happen because of the halfing mechanism, which decreases the bounty for mining each block by 50% each 210 000 blocks or roughly 4 years. There were 2 halfings in the past, 50 to 25 to 12,5 BTC, and the next one is going to take place in May 2020, when 12,5 BTC will turn into 6,25 BTC. So, all in all there should be 34 such cycles to mine all 21 million coins.
At the same time, Chainalysis report that at this point 4,85 million coins are in daily circulation. 4 million BTC may be lost or frozen forever because of the lost access to some secure wallets.
