A lot of discussion on Steemit is dedicated to questions: what is really STEEM mining rate and what is the inflation programmed per year. I tried to understand how it works and made some investigation.
The STEEM White paper says:
Then the network starts rewarding users who convert to SP. At this point, STEEM grows at a rate of approximately 800 STEEM per minute due to the combined effects of the various Contribution Rewards ...
When the various individual components of the 800 STEEM per minute rate reach their respective percentage-based floors, each floor halts the fall in its component of the rate. This in turn means that, over the long term, the nominal rate will rise from 800 STEEM per minute to the (time-varying, supply-dependent) value needed to maintain a constant annualized growth rate of 10% for the Contribution Incentives, and a constant annualized growth rate of 100% for the combined effect of the Contribution Incentives and the Power Incentives.
I copied blockchain data from steemd.com during this month and calculate actual mining rates:
>>> head_block_number time virtual_supply blocks_delta \
1 3741103 2016-08-02 21:02:45 1.200000e+08 48
2 4169242 2016-08-17 19:44:12 1.336217e+08 428139
3 4309722 2016-08-22 17:49:42 1.379500e+08 140480
time_delta steem_delta sec_delta sec_per_block steem_per_block \
1 0 days 00:02:24 1489.840 144 3.000000 31.038333
2 14 days 22:41:27 13621729.487 1291287 3.016046 31.816138
3 4 days 22:05:30 4328305.580 425130 3.026267 30.810831
steem_per_sec steem_per_min
1 10.346111 620.766667
2 10.548956 632.937348
3 10.181134 610.868052
So, you could see that the block generated every 3 seconds and contains 30 STEEM, in other words it was generated about 600 STEEM per minute. It is still less than declared 800 per minute rate.
If this rate will remain the same, the annual emission displays 600STEEM * 60min * 24h * 365d = 315,360,000 STEEM. During the next year the supply will increase on 315M STEEM / 138M STEEM = 2.28 times or on 228%.
It is still not clear for me: how STEEM rate is adjusted and where is promised 100% annual growth?
Confirmation for my calculation is very appreciated in comments. I will be thankful for any clarification of the matter.