For the 15th consecutive year, Exxon Mobil shareholders on Wednesday rejected a proposal which sought to ban discrimination based on sexual orientation and gender identity as part of the company's equal employment opportunity (EEO) policy.

Support for the change decreased slightly over last year, down .3 percent to 19.5 percent.

The measure, backed by New York Comptroller Thomas DiNapoli, fared better in 2012, receiving support from 20.6 percent of shareholders.

In a statement to shareholders, Exxon Mobil's board of directors advised against the change, calling it “unnecessary.”

“The Board has reviewed in detail ExxonMobil's existing global policies that prohibit all forms of discrimination, including those based on sexual orientation and gender identity, in any company workplace, anywhere in the world. In fact, ExxonMobil's policies go beyond the law and prohibit any form of discrimination. Based on these existing all-inclusive, zero-tolerance policies, the Board believes the proposal is unnecessary,” the statement read.

Fred Sainz, vice president of communications at the Human Rights Campaign (HRC), said that without anti-discrimination policies, it would be reasonable to question the oil giant's commitment to equality.

“If ExxonMobil is as committed to zero-tolerance as they claim, there's simply no reason to [not] have fully-inclusive policies,” Sainz told gay weekly the Washington Blade. “Until then, their commitment to equality will rightly be questioned.”

Last year, Exxon Mobil extended benefits to the spouses of gay employees.