As of May 29, 2020, the AZHS website lists 18,465 confirmed cases in the state. One would assume a confirmed case has a positive test to back this conclusion. However, the positive tests listed on the website (209,813 PCT tests with 6.7% positive, and 87,682 serology tests with 2.9% positive) total 16,599. That leaves at least 1865 confirmed cases without a matching test.

Furthermore, if AZHS counts a positive serology test as a confirmed case, what date do they attribute it too? A positive serology test indicates at best, a past infection, so attributing it to any date (date of test?) would invalidate the data as presented. If the confirmed cases don't include positive serology tests, there would be 4,408 cases without a confirming test.

Without an explanation of methodology your data is therefore suspect. As is, any attempt to draw conclusions from this data is useless.