Quote from: farhaan on February 15, 2018, 11:27:42 PM

Yes that has happened already and its said that almost three million coins have been lost due to such reason which has lessened the total availability of bitcoins from 21 million to just 17 million bitcoins along with one million bitcoins of satoshi which too remains unused.

You cannot say with certainty that any coins have been definitely lost (other than in cases like "bitcoin eater" address and similar). You can only make assumptions (based on inactivity etc) and make estimations.

ps can you share the source of that 3 mil estimate?

On the side note: I reckon that there must be quite significant, cumulative amount of bitcoins simply abandoned by people deleting old wallets with fractions of BTC in them, worth almost nothing at the time in fiat terms.