Arizona came in first in a nationwide ranking of services for people with intellectual and developmental disabilities. (Shutterstock)

An annual ranking of states offering the best services for people with intellectual and developmental disabilities reveals a familiar but evolving landscape.

The analysis of disability services in all 50 states and the District of Columbia being released Thursday by United Cerebral Palsy finds top performers spanning the map. In previous years, the best services were largely clustered in the Northeast and West.

Arizona claimed the number one slot in the ranking for the third year in a row. Also rounding out the 10 best on this year’s list are Michigan, Hawaii, Georgia, New York, South Carolina, Maine, Massachusetts, Ohio and Missouri.

The analysis factors each state’s approach to promoting independence and productivity, ensuring quality and safety, keeping families together and reaching people in need.

Nationally, almost 317,000 people remain on waiting lists for home and community-based services, according to the report, which is largely based on data from 2012, the most recent year available.

Some 38 states serve at least 80 percent of people with developmental disabilities in the community. Meanwhile, just 10 states have one-third or more of their residents with developmental disabilities working in competitive employment, the report found.

As in past years, top-tier services were found in both big and small states, those with rich and poor demographics, jurisdictions with high and low taxes as well as those with varying levels of per-person spending on disability services.

The report flags Arkansas, Illinois, Texas and Mississippi — which ranked last for the eighth year in a row — for repeatedly coming in at or near the bottom of the list.