This open source app reads subscan and tries to collect your total rewards from the last week (28 eras) for each validator you currenty nominate, and display it as a percentage. The idea is to provide a bit of info on how your nomination mix is working.

Nominumbers runs in your browser, no data is collected - you can also download the zip and use it locally on your device. The plan is to extend this in the future using treasury funds to make it easier for nominators to collect information on staking rewards. 

https://twitter.com/ruitao_su/status/1208305894083022848

To Dave for: https://playing-with-dust.github.io/nominumbers/