The rate that new tokens are generated was set to 9.5% per year starting in December 2016,
and decreases at a rate of 0.01% every 250,000 blocks, or about 0.5% per year. The inflation
will continue decreasing at this rate until it reaches 0.95%, after a period of approximately 20.5
years.
Of the supply of new tokens created by the Steem blockchain every year, 75% of those tokens
compose the “rewards pool” which are distributed to content creators and content curators.
15% are distributed to vested token holders, and 10% are distributed to Witnesses, the block
producers cooperating inside Steem’s DPoS consensus protocol.
How so? And excuse the questioner.
Every time a block is created, steem is created too. New steem are distributed to witnesses, authors and curators (or bots, jajaa)
I see, so that's how STEEMs are born.
I've never really been interested in knowing where they came from til now
This is from the blue paper:
This means that there is a fixed amount of STEEM to be created up to 20 years from now. And most of it is for rewards. Nice!