A common question were getting at HuffPost Pollster lately is: Why isnt Libertarian Party presidential nominee Gary Johnson included in your charts? Occasionally it's more of a screed than a question, but the point is basically the same.

Rest assured, we are not part of some conspiracy to keep Johnson from getting support. Our decisions are based completely on how pollsters are dealing with Johnson -- and that varies a lot.

Fifteen pollsters conducted 25 polls in the month of May. The table shows a summary of how pollsters handled -- or didnt handle -- third-party candidates in their most recent surveys.

Only three pollsters of the 15 included Johnson in their polls by name: the Democratic firm Public Policy Polling, Fox News and Quinnipiac University. HuffPost Pollster needs at least five polls on a candidate to be able to calculate a trend line before we can include them in our charts, and these pollsters have only one poll each in the last month.