Despite last year's historic U.S. Supreme Court ruling that legalized same-sex marriage nationwide, LGBT Americans still lack inclusive civil rights protections in most states, shows a new national report.

On Wednesday, the Human Rights Campaign (HRC) and the Equality Federation released their "State Equality Index," a summary of state-level laws and policies impacting LGBT people. The index places states in four categories based on their LGBT-related laws and policies. 

The index's lowest-rated category, "High Priority to Achieve Basic Equality," includes 28 states such as Arizona, North Carolina, Texas and Florida.

"Even with marriage equality the law of the land, the battle for LGBT rights at the state level continues to be a story of successes and setbacks," HRC President Chad Griffin said in a statement. "Though a number of states are expanding access to non-discrimination protections for LGBT people and their families, a majority of states are still struggling to reach even a basic level of equality for LGBT people."

"This year will be one of our most challenging yet, with our opponents in more than two dozen states pushing deeply harmful laws that undermine critical protections in the guise of 'religious liberty,'" Griffin added. "Equally troubling are disgraceful bills targeting the transgender community -- from preventing transgender people from using public facilities, including bathrooms, that accord with their gender identity, to denying them the ability to make gender and name changes on crucial identification documents."

Illinois -- in which LGBT people have protections from discrimination based on sexual orientation and gender identity -- joined five states and the District of Columbia in the report's highest-performing category, "Working Toward Innovative Equality." Other states in that category include California, Colorado, Connecticut, Oregon and Washington.

"These states and the nation's capital have robust LGBT non-discrimination laws covering employment, housing and public accommodations, as well as protections in the realm of credit, insurance and jury selection," reads HRC's report summary. "Most allow transgender people to change official documents to reflect their gender identity. Almost all bar private insurers from banning transition-related healthcare. LGBT youth are protected by anti-bullying laws, as well as innovative measures in some states that address conversion therapy, inclusive juvenile justice policies, homelessness and sexual education."