The filters on pgc stats and maps are not created by the users but by the website. There is an exception that you can create som "custom filters" from the menu with your name to the fare right.
But there are tools for most thing you would need.
What you are looking for is "Map - Hidden Month" in the tools menu
The result for the US for you will be the link below: cache for missing months
You have 11 different month with 0 finds
If you what two per month you need to use the loop filter and set it to 2
But you need to be a paying member to do that. You have 30 month with <2 finds
One thing to notice is that the result is limited to 1000 caches and on 9 different missing months will be on the US map. (no warning and bugg reported)
it is the most recent month that are missing September 2001 and September 2016 and october 2001 is likly not complete. The current month is not in the tool for som reason but can be done in map compare and is no problem with 448 caches in, Texas where i suspect you live, and the has not ended
Do a filter for missing month <2003 in Texas here i suspect you live
You can select multiple states if you are a paying member you can select multiple states. Splitting in <=July 2001 and August & sepetmber 2001
But log the missing near you first and the missing number will be quickly reduced
I recommend this video https://www.youtube.com/watch?v=DjnbFQjvxtA
Finding good caches with high %FP or wilson score i recomended.
And filling the DT matrix