At the moment the Radix Wallet does not show a separate amount for rewards earned from staking. However, the following community websites can be used to view this information:
Looks like Stake Tracker is no longer working.
Fixed the url for StakeTracker - should work now
https://xrdscan.com/ works too (freemium?)
Freemium is for first 3 weeks only, next are 2 levels to stake to get membership Pro (5%) and Elite (10%).