Custom Availabilty Servers Report

Custom Availabilty Servers Report

Hi,
 
Wish to create a custom availability for the servers report because the existing availability servers report does not meet our requirement.
 
Therefore, intend to do custom report by ourselves.
We are able to look at the fields however indicate the number which do not understand.
Have attached a drawn report for easier to v irtualize.
What we need is to tabulate the availability for each month on the same report so that we will know the trend.   
Does anyone know which field to pull from opsmanger tables?
 
Thanks
/Jason

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