Here are some links to the CDC's statistics and maps on Lyme disease for those interested:
https://www.cdc.gov/lyme/stats/graphs.html
https://www.cdc.gov/lyme/stats/maps.html
https://www.cdc.gov/lyme/stats/tables.html
As an aside, it's tricky interpreting certain stats regarding epidemiology. The incidence is the number of new cases in the population in a given time frame, and prevalence is the total number of people known to have the disease in the population. Sometime a disease can appear to be "on the rise" because there is increased surveillance and screening for the disease, or because diagnostic methods have improved, which naturally lead to an increased incidence and prevalence.
Disclaimer: I'm not arguing that Lyme Disease isn't real, isn't serious, or anything along those lines. But from a medical perspective, we deal with fear of Lyme way more often than the actual disease. Some parents will bring their child into the clinic every time they think they may have seen a tick within arm's reach of them. And when someone presents with an attached tick, it's more often than not an adult wood tick (which can transmit RMSF and tularemia but are not B. Burgdorfi vectors).
When you are bitten by a tick, or any insect, some inflammatory response is expected, i.e. your skin will probably turn red. It doesn't automatically mean it's erythema migrans (bull's eye rash). But to muddy the waters even further, as little as 50-80% of confirmed LD cases had the EM sign, and many don't recall a tick bite whatsoever.
But if you are in an endemic area, clinical suspicion for LD is high, we should be able to prove you have the disease with lab tests, right? Well, unfortunately Borrelia are notoriously difficult to culture, so that's out. The CDC recommends a two-step testing process.
Step 1 is the Enzyme Immunoassay (EIA). If your EIA is negative, LD is ruled out. If it is positive or "indeterminate" (2nd most common outcome after negative in my experience), you move on to the Western blot which looks for antigenic proteins associated with the disease. It is considered positive if 2 specific bands are visualized or if at least 5 of a list of 10 other bands are seen. The problem is that these bands can take up to 6 weeks after exposure to become detectable. If you have no idea when/if you were actually exposed, this test is a shot in the dark. To top it all off, it can also come back "mildly" to "moderately" positive for LD.
So if your EIA is negative, or if your WB is 2/2 or 5+/10 positive, we can give you a definitive answer. Otherwise, it comes down to clinical judgment and weighing the risks and benefits of treatment. If you were bitten by a tick, got a rash, had no drug allergies, the safer play is to assume LD, give antibiotics, and forgo the serologic testing that may or may not give an answer.
TLDR - Lyme Disease is complicated.