You can see who has minted during the last 24 hours by using the block explorer's network page. Comparing today's results with tomorrow's results should give a rough indication how many people are staking 24/7.
Here's today's results.
https://chainz.cryptoid.info/mint/#!network
It shows the number of clients seen by fairglu's daemon during the last 24hours.
It says nothing about minting / online status / online time.
Btw. next Mintcoin version should get another client / protocol version. It would be nice to see on which version the people are.
Example:
https://chainz.cryptoid.info/zeit/#!networkCheers,
Ray