The Bitcoin network has been active since the genesis block on 3-Jan-2009, and over that time, coins have been mined, lost, bought, and sold. As investors accumulate and store (or lose) coins for longer periods of time, we can categorise them based on how long it has been since they last moved on-chain.
This chart displays an overlay of multiple Supply Last Active variants, each shown as a percentage of Circulating Supply.
As coins are accumulated by longer-term investors, these metrics will tend to rise. Conversely, as long-term investors spend and distribute their coins, this metric will decline, with older coins becoming young again as they change hands.
Note: This metric will naturally drift higher due to the growing share of coins held for a very long time or lost (loss of access to private keys).