Q: When did Apple become ADA Compliant and why?

I am doing a research paper on any IT product or product line that was impacted by either the ADA or Section 508.

I can see how happy the ADA is with all Apple products, but I need to know when Apple actually followed the ADA guidelines.

I am a student at Colorado Technical University working on getting my B.A. in Information and Technology.

Thank you in advance for your time,