A scientific publication titled Global Web Accessibility Analysis of National Government Portals and Ministry Web Sites (Morten Goodwin, Deniz Susar, Annika Nietzio, Mikael Snaprud, Christian S. Jensen) was recently published.
The publication presents web accessibility benchmarking methodology, and uses this methodology to present a survey on the accessibility of public web sites in the 192 United Nations Member States. It further identifies common properties of Member States that have accessible and inaccessible Web sites and shows that implementing antidisability discrimination laws is highly beneficial for the accessibility of Web sites, while signing the UN Rights and Dignity of Persons with Disabilities has had no such effect yet. The article also demonstrates that, despite the commonly held assumption to the contrary, mature, high-quality Web sites are more accessible than lower quality ones. Moreover, Web accessibility conformance claims by Web site owners are generally exaggerated.
The countries with web sites that receive the best accessibility scores are:
The survey also shows that the economy of a country influences the accessibility of web sites, so that, not surprisingly, wealthy countries have more accessible web sites than poor countries. However, the study shows that accessibility laws have more impact than the financial status. Thus, it is not necessarily costly to make web sites accessible. It is however important to have well established accessibility laws which are actively followed up.
(Full disclosure: I am a co-author of the paper)