The difficulty is in line with the computational power needed to mine BTC blocks.
On March 4, there was a slight reduction in the BTC network difficulty, causing a decline from 27.96 trillion to 27.55 trillion.
It is expected that the remaining 2 million BTC will be mined by the year 2140, due to factors such as halving.
On March 30, a Terra wallet belonging to Luna Foundation Guard accumulated $139 million BTC in Bitcoin, bringing the total amassed BTC in the coffers to 31,000, or $1.47 billion worth of BTC.
Reports reveal that the Terra wallet started accumulating large amounts of BTC in January this year and a single BTC has not left the coffers since then.