15% of the total inflation, which is 8.7% annually at this time, is given to SP holders. 15% of 8.7% is 1.3%, which is how much you directly benefit from powering up as opposed to keeping your STEEM in liquid form in a year.
This is not the correct calculation. 15% of the inflation rate seems correct, but it’s not. It’s a bit higher, and here’s why:
https://steemit.com/steempower/@preparedwombat/the-steem-power-you-earn-for-holding-steem-power
Thanks for the clarification! When you take virtual supply into account, the percentage goes up from about 1.3% to about 1.95%.