Block rewards are calculated as such:
So if the reserve has 220m rune, a single block will emit ~5.8 Rune from the reserve, which means 2/3rds to that is awarded to the node operators (~3.8) and is divided up between each operator. The rest is paid to Liquidity providers.
The emission curve is designed to start at around 30% APR and target 2% after 10 years. At that point, the majority of the revenue will come from fees.