Help to constructing visualization

[jorjao (Jorge Sá)]

I'm new in Kibana.
My data is that of tasks in which I indicate the start date, expected date of closure (due) and the end date.

I need to build a visualization that tells me the percentage of tasks that met the deadline per month.
In other words, I needed to know the total number of tasks that fulfilled the deadline and to divide by all the tasks that were closed that month.
How can I do this in visualization?
I have already been able to do both counts using different metrics but how to divide one by the other and only show this separate value per month?

[Marius_Dragomir]

You can do the division and display per month by using TSVB. The interface of the builder is similar and for calculating the percentages you should used the Math aggregation (which is only available in TSVB)

[jorjao (Jorge Sá)]

Thanks for your response.
I need a help in two questions.
1 - I constroy two visualization and in third i will use math aggregation but this option is disabled.
I only have the options (metric aggregations) available.
what i do wrong? how enable math aggreation.

2 - how use filter in date field? I use aggregation count and i need filter endTime if have value. I use the expression endTime: "exists", but the result is 0 (wrong because tasks have endTime).
how filter?