Problem to filter value by month and year

Hello, I hope you are well

I have this dataset, where I need to get the percentage in relation to the total, of the certain number of claims that a company has.

What I need to do is filter for the year 2020, for example, in March, and the calculated percentage is the one that corresponds to the total volume of March.

This is my dataset

And this is the measurement I created, but it only works if I filter per year. If I filter by month, it does nothing.

% total = sum ('public web_ale_topn_alertas' [contador]) / CALCULATE (sum ('public web_ale_topn_alertas' [contador]), ALLSELECTED ('public web_ale_topn_alertas'))

Thank you very much for the help!