National Organisation for Marriage (NOM), the American campaign group that is staunchly opposed to LGBT equality, has seen a large drop in its financial donations.

According to Human Rights Campaign (HRC), newly obtained financial documents show NOM raised $6.2 million (£3.9 million) last year, which is significantly lower than the $9.1 million (£5.7 million) it raised in 2010.

HRC notes that NOM has typically seen steady growth since it started back in 2007 to fight for California’s Proposition 8, the referendum which halted same-sex marriages in the state.

According to a document seen by HRC, just two individual donors were responsible for 75% of the group’s funding. Each contributor gave an estimated $2.4 million (£1.5 million).

In a statement, HRC’s Fred Sainz said: “NOM’s own financial records are serving as the latest proof that support for LGBT equality is common-sense and mainstream”.

He added: “NOM is nothing more than a conduit channelling the anti-gay agenda of a few secretive, wealthy donors.”

Despite campaigning aggressively, NOM failed in its bid to persuade a majority of residents in four US states to vote against marriage equality measures during this month’s US elections.