this transaction actually "generates" new coins (sum of outputs is larger than its input).
That's why it's called interest.
The first 2 transactions are always related to the generation of the Proof Of Stake block. If there are more than 2 transactions then there are actual coins moving about in that block.
If there are more than 2 transactions in the block then a portion of the extra coins are actually fees and not "new coins".
The coins being generated by Proof Of Stake is actually very low. I'd estimate about 20-40 new coins a day at most.