select certain data values from non-uniform distributed data table

Dear all,

I need to get a range of data values which greater or equal to 1 for a particular year and months (group), hence to calculate the 95 percentile of this data value range.

I got a very large data size and my data not everyday of the month got value, not uniformly distributed for days of the month.

Im not sure you all understand what Im trying to find. Here, I attached the sample workbook. Hope you can understand my question better.

Any ideas and help will be appreciated. Thanks in advance. cheers!

Not certain I completely understand, but does this help get you what you are looking for?