Create average availability for multiple servers?

Hi,

I have created a table visualization where the availability (status:up) for each monitor.name is being presented in percentage.

Now I would like to create a visualization that sums all availability for all servers up and creates the average availability value for each day.
i.e. take 4x 100% + 2x 99,645 and divide with 6 (amount of monitors).

I just want to have the correct calculation here and get back value in percentage.

How can I do this?