I was reading somewhere by 2030 98% of bitcoin will have been mined.
So I wondered if 90% had already been reached: not yet, so I calculated what day the bitcoin that adds up to 90% will be mined, and it coincides with Christmas day!
For the curious, the calculations:
90% of 21M = 18,900,000 bitcoins, will be reached in block #715,715 (630,000 + 85,715): 210,000 * (50 + 25 + 12.5) + 85,715 * 6.125 = 18,900,004 bitcoin. Block #710,118 was mined on Nov 17 at 11:00 GMT. 5597 blocks remaining / 144 (blocks/day) = 38.8 days = 25th to 26th Dec., a few hours should be subtracted by the current upward trend of the hashrate.
TLDR: On block #715,715, most probably Christmas Day or eve, 90% of bitcoins will have been mined!