Market Dominance is calculated by taking a coins market capitalization (market cap), and dividing it by the total market capitalization of the cryptocurrency market.

For example:

Bitcoin's market cap: $100,000,000,000
Entire cryptocurrency market cap: $200,000,000,000

$100,000,000,000/$200,000,000,000 = 50%

Bitcoin's Market Dominance in this example = 50%

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