Not really sure what the APR is but the PoS stake started with 50, 25, 10 and now 5.
Next block halving will occur on 100,000 which is a few days from now.
Stake will be 2.5 per block.
I didn't realise that there had already been a few block halvings. I should have staked from the beginning! Is every block period equal in length? How long is that exactly?