Here is a map showing CDC reported numbers in the U.S.A. You should be able to click on the map to enlarge. That little note under the map is very important...it says:
Note: CDC says Lyme disease is under-reported and that only about 10% of cases that meet CDC surveillance criteria are actually reported to the CDC. (For example Oklahoma 362 reported cases=3,620 probable cases meeting CDC criteria)...putting Washington's numbers up near 2,000. This doesn't take into account the many cases not presenting enough bands to qualify for CDC surveillance criteria but still having Lyme disease. You can see how the numbers begin to add up. Lyme is the fastest-growing vector-borne disease in the world.
For more information, please check out the International Lyme and Associated Diseases Society (ILADS) or the Lyme Disease Association (LDA)