Well how it works is that 3.5 DEC tokens will be added to the reward pool with every Hive block, so with ~28800 blocks per day times 3.5 DEC is roughly 1M DEC / day. Then if the current DEC market price is 10% above $0.001 then 3.85 DEC (10% more than 3.5) will be added to the reward pool for each block and vice versa if the market price is lower.
Then the DEC in the reward pool is given out to players as they win ranked battles. You can check how much DEC is in the reward pool at any time at the following URL: https://game-api.splinterlands.com/players/balances?token_type=DEC&players=$REWARD_POOL