In order to calculate the quantity of STEEM that is being created each day in Steem Blockchain, it is necessary to have the data like inflation, the total virtual supply of STEEM, the number of blocks produced per year, etc.
The inflation figure as obtained from Steemdb is 8.3353%

Total virtual supply means (all liquid STEEM+all STEEM Power+the total supply of SBD in STEEM Equivalent). The approximate figure can be obtained from Steemd.

Total virtual supply= 370948748
In Steem Blockchain, one block is produced every 3 seconds.
Number of blocks produced per year= (60 * 60 * 24 * 365)/3= 10512000
Inflation= 8.3353 %= 0.083353
New STEEM that is being created per block= (Virtual Supply * Inflation)/(Number of blocks produced per year)
=> New STEEM created per block= (370948748 * 0.083353)/10512000= 2.94 STEEM
=> New STEEM created per day= (60/3) * 60 * 24 * (2.94)= 84672 STEEM
Distribution
- For PoB(Content creator & Curator)= 65%= 0.65 * 84672= 55036.8 STEEM
- For Block producer= 10%= 0.1 * 84672= 8467.2 STEEM
- For Vested token holders= 15%= 0.15 * 84672= 12700.8 STEEM
- For SPS= 10%= 0.1 * 84672= 8467.2 STEEM

Note- Please do note that the exact amount of STEEM that is being created will slightly vary each day, considering the fact that the inflation in on a decreasing gradient(at a rate of 0.5% decrease per year) and the virtual supply is also different each day, as new STEEM are being added to the total virtual supply each day. Although it will not very by a big margin on day to day basis, but definitely it varies significantly on yearly basis.
Unless otherwise stated, all are my original works.