Since Bitcoin (BTC) was launched almost a decade ago, 17 million units of the leading virtual currency with regards to market capitalization have been mined so far. With a token limit placed at 21 million bitcoins it means there are only four million more bitcoins left to mine.
In every interval of 10 minutes, a new block of bitcoin is created by miners of the digital currency. These blocks are basically subgroups of the individuals or entities which are operating computer nodes with a view to keeping bitcoin running. As new transactions keep being added all the data involving bitcoin transactions is added and updated by powerful computers.
In order to verify transactions mining nodes are required and in turn the reward that is given to miners is bitcoin. For every new data block or the verified bitcoin transactions miners are rewarded with a total of 12.5 million bitcoins. This means that every single day there are 1800 bitcoins that are mined every day.
However this will not always be the case. This is because with every 210,000 bitcoin blocks created the rewards are halved. Some years ago the reward for every block mined was 50 bitcoins but this fell to 25 bitcoins in 2012. The current reward of 12.5 bitcoins per block came into force in 2016 in this process that is technically known as halving. Late next year or early 2020 the next halving will take place. The purpose of halving is to ensure that the digital currency gets more valuable with the passage of time as a result of limited supply.
Another aim of the halving process is to ensure that the rewards are kept relatively proportional and also prevent the supply from being in the control of the miners. Consequently this has the implication of reducing the rate at which bitcoin is mined and thus as time goes on the process gets slower and takes longer.
In a sense bitcoin mimics gold and the mining terminology was borrowed from how the precious metal is produced as well as its scarcity. However there are differences in that the scarcity of gold is naturally occurring while that of bitcoin is determined by the software or code. Also the mining of bitcoin involves using computer processing power to conduct complex math problems and get bitcoins as a reward. The mining of Gold on the other is done by physically extracting the metal from the earth.