Steem Yearly Inflation Table
According to @fyrstikken post
Inflation decreases by 0.5% yearly from 9.5% inflation from year 1, and will stop stop at 1% inflation at year 18.
*Note that Inflation is really a good thing on steem as it helps the coins to be more distributed to users and be more used and in “theory” will make more steem more appreciated
According @ilyastarar post
New coins are from inflation are distributed as follows:
75 % Reward pool
15% SP holders
10% Witnesses
Steem's New Supply Yearly Distribution table
Conclusion:
If you really believe in steem and looking for a long term investment, powering up is a must so that you can utilize the new coin distribution by simply voting and contributing content.