Mined Volume required to maintain Index level 5!

Hello,
I found a table on “the Mined Volume required to maintain Index level”
For level 5 it gives 12,000,000m3/day. But at the moment when I mine a total of around 86,000 m3 the index goes up by 1%. Which would make 100% of the level 8,600,000 m3. and suddenly 24% which corresponds to a day would be approximately 2,000,000 m3.
So my question is for level 5 how much do you have to mine per day to maintain the index? 2,000,000 m3 or 12,000,000 m3
Sorry for the google translate errors.