Blank Spots in Heat Map

[DaniCalifornia]

I have a heat map with sum totals by county and year. I am limiting it to just the top 10 counties by total. When I am looking at all of them, I have holes in the heat map where there is no value. When I drill to that county though, there are values for those years. They are neither the highest or lowest values either, so it's not some limitation cutting off my lowest values. 

I am at a loss as to why these values do not appear in my heat map. Any ideas? 

[DaniCalifornia · Accepted solution]

Figured it out. I just realized that I have 11 counties, not 10 and that each of my years has exactly one blank spot. 

It's not looking at the sum total across all years, but the sum total for each year and it happened to return a relatively predictable set of counties for each of the years. The blank spots are below the threshold of top 10 for that year, even though they aren't the lowest value when I look at that county in particular. 

I would be curious to know how to return the top 10 across ALL years/ the entire data set, but for this purpose, I think the way it returns is fine, as long as I have an explanation for it 🙂