Bitcoin miners are paid according to their share of work done, rather than their share of the total number of blocks mined. The system is designed so that each block contains a certain amount of “work”, and miners are rewarded according to the amount of work they contributed to solving that block.
For example, if a miner contributed 1% of the total work done on a block, they would receive 1% of the total reward for that block.
The total reward for a block is currently 12.5 BTC, but this will halves every 210,000 blocks (approximately every 4 years). So, if a miner were to mine a block right now, they would receive 12.5 BTC as a reward.
However, if they waited until after the halving to mine a block, they would only receive 6.25 BTC as a reward.
The actual amount of BTC paid out to miners can vary quite a bit from day to day, due to the volatile nature of the Bitcoin price. However, over the long term, miners can expect to earn a fairly consistent income from mining Bitcoin.