You can explain all of it, authors, curation, staking, witness, even a small part of DHF, except interest and most of the DHF.
About curation. The overall inflation is set to 6%, for all the hive supply. Curation rewards are 32.5% out of the infaltion, 32.5% * 6% = 1.95% CR .... but this is given out only to staked hive, or HP, curently at 182M HP out of the 450M HIVE, or around 40%. So you have 1.95%/40% = close to 5%. Furthermore not all of the 182M HP is active and votings, or there is around 20% idle and that further pushes the CR rewards to 7% and above... you can do the similar math with staking rewards, that are 15% out of 6%...
But the sums that we are paying out from the DHF are unproportianly big for our curent market cap. It is possible becouse there is simple to much tokens in the DHF as a result of the STEEM premine, and then later we trasfered those tokens in the DHF with the Hive Hardfork in 2020. We are spending a premine to pay development work. Also the interest for HBD is on top of the inflation.